Polymerization process with living characteristics and polymers made therefrom

ABSTRACT

A free radical polymerization process suitable for synthesizing polymers is disclosed. The process utilizes novel sulfur based chain transfer agents and is widely compatible over a range of monomers and reaction conditions. Novel polymers having low polydispersity and predictably specific polymer architecture and molecular weight are produced by the process. The polymers produced by the process are suitable for use as binders in automotive OEM and refinish coatings.

This application is a 35 U.S.C. §371 of PCT/US98/26428 filed on Dec. 11,1998, which claims the benefit of U.S. Provisional Nos. 60/068,074,60/069,981 and 60/068,157 all filed on Dec. 18, 1997.

BACKGROUND OF THE INVENTION

The present invention generally relates to a free radical polymerizationprocess and particularly relates to a free radical polymerizationprocess utilizing chain transfer agents (CTAs) and to polymers madetherefrom.

There is increasing interest in developing polymerization processes thatcan be predictably controlled to produce polymers having specificallydesired structures. One of the means for achieving such results isthrough a process of living polymerization. Such a process provides ahigher degree of control during the synthesis of polymers havingpredictably well defined structures and properties as compared topolymers made by conventional polymerization processes.

Certain xanthate and dithiocarbamate derivatives of the followingformula 1:

where Q=O(alkyl) or N(alkyl)₂, respectively have been shown to confersome of the characteristics of living polymerization when used asphotoinitiators in polymerization processes (see for example Otsu etal., U.S. Pat. No. 5,314,962). Such a process where radicals aregenerated by direct photolysis of the xanthate or dithiocarbamatederivative do not form part of this invention. See also Niwa et al.(Makromol. Chem., 189, 2187 (1988)) and Otsu et al. (Macromolecules 19,287 (1986)).

Free radical polymerizations in the presence of chain transfer agents(CTAs) represented by formula 1 (where Q=Z′ and R are as defined herein)have been disclosed by Le et al. in Int. Patent Application WO 98/01478,which discloses, that since dithiocarbamate and xanthate derivativesdisclosed therein have very low transfer constants they are thereforeineffective in conferring living characteristics on a free radicalpolymerization. However, we have surprisingly found that by appropriateselection of substituents (Q) or the monomer these agents have highchain transfer constants and are effective in conferring livingcharacteristics to a free radical polymerization. The CTAs of thepresent invention can also advantageously introduce novel end groupfunctionalities into the resulting polymers.

Other process is disclosed in EP 0592 283 A1. The process is directed tosynthesizing hydroxylated telechelic polymers obtained in the presenceof thiuram sulfide, which acts as an initiator, chain transfer agent anda termination agent. Such agents are commonly referred to as iniferters.

Another process is disclosed in EP 0286 376 A2. The process is directedto synthesizing ABA type block copolymers through photodecomposition ofdithiocarbamate group-contaning polymeric intermediates.

Yet another process is disclosed in EP 0349 232 A2. The process isdirected to synthesizing acrylic block copolymers by using an iniferter.

Still another process is disclosed in EP 0449 619 A2. The process isdirected to synthesizing adhesives by using radiation curablephotoiniferters.

Another process is disclosed in EP 0421 149 A1. The process is directedto synthesizing chloroprene polymers having dithiocarbamate groups atboth termini of the chloroprene polymeric chain.

Chem. Abstract 74:87665 Apr. 4, 1971) and JP-B-45034804 disclosethiocarbamate iniferter as a polymerization catalyst.

Another Chem. Abstract 72:53948 Mar. 3, 1970) and Agr. Biol. Chem.(1969), 33 (12), 1691-1699 disclose the use of thiocarbonates asherbicides.

Yet another Chem. Abstract 125:276423 Nov. 11, 1996) and J. Am. Chem.Soc. (1996), 118 (38), 9190-9191 disclose a process for synthesizingdeoxygenerated sugar derivatives obtained by heating a variety ofcarbohydrate xanthate containing electron withdrawing ester groups incyclohexane.

STATEMENT OF THE INVENTION

The present invention is directed to a process for producing a polymer,said process comprising polymerizing a monomer mix into said polymer inthe presence of a source of free radicals and a chain transfer agenthaving a transfer constant in the range of from 0.1 to 5000, said chaintransfer agent having the following formula:

wherein when D is D1 of the following formula:

then p is in the range of from 1 to 200, E is Z′ and said transfer agentis of the following formula:

wherein when D is D2 of the following formula:

then p is in the range of from 1 to 200, E is E1 or E2 and said transferagent is of the following formula:

wherein when D is D3 of the following formula:

then p′ is in the range of from 2 to 200, E is Z, E1 or E2 and saidtransfer agent is of the following formula:

wherein when D is D4 of the following formula:

—S—R′

then E is E3 or E4 and said transfer agent is of the following formula:

 where in all of the above:

R is a p-valent moiety derived from a moiety selected from the groupconsisting of substituted or unsubstituted alkane, substituted orunsubstituted alkene, substituted or unsubstituted arene, unsaturated oraromatic carbocyclic ring, unsaturated or saturated heterocyclic ring,an organometallic species, and a polymer chain, R. being a free radicalleaving group resulting from R that initiates free radicalpolymerization;

R* and R′ are monovalent moieties independently selected from the groupconsisting of a substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl, unsaturated oraromatic carbocyclic ring, unsaturated or saturated heterocyclic ring,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxy, substituted or unsubstituted dialkylamino, an organometallicspecies, and a polymer chain, R*. being a free radical leaving groupresulting from R* that initiates free radical polymerization;

X is selected from the group consisting of a substituted orunsubstituted methine, nitrogen, and a conjugating group;

Z′ is selected from the group consisting of E1, E2, halogen, substitutedor unsubstituted alkyl, substituted or unsubstituted alkenyl,substituted or unsubstituted aryl, substituted or unsubstitutedheterocyclyl, substituted or unsubstituted alkylthio, substituted orunsubstituted alkoxycarbonyl, substituted or unsubstituted —COOR″,carboxy, substituted or unsubstituted —CONR″₂, cyano, —P(═O)(OR″)₂,—P(═O)R″₂;

R″ is selected from the group consisting of substituted or unsubstitutedalkyl, substituted or unsubstituted alkenyl, substituted orunsubstituted aryl, substituted or unsubstituted heterocyclyl,substituted or unsubstituted aralkyl, substituted or unsubstitutedalkaryl, and a combination thereof;

Z″ is a p′-valent moiety derived from a moiety selected from the groupconsisting of a substituted or unsubstituted alkane, substituted orunsubstituted alkene, substituted or unsubstituted arene, substituted orunsubstituted heterocycle, a polymer chain, an organometallic species,and a combination thereof;

Z is selected from the group consisting of a halogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted aryl, substituted or unsubstituted heterocyclyl,substituted or unsubstituted aryl, substituted or unsubstitutedalkoxycarbonyl, substituted or unsubstituted alkylthio, substituted orunsubstituted alkoxycarbonyl, substituted or unsubstituted —COOR″,carboxy, substituted or unsubstituted —CONR″₂, cyano, —P(═O)(OR″)₂,—P(═O)R″₂;

E1 is a substituent functionality derived from a substituted orunsubstituted heterocycle attached via a nitrogen atom, or is of thefollowing formula:

 wherein G and J are independently selected from the group consisting ofhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkoxy, substitutedor unsubstituted acyl, substituted or unsubstituted aroyl, substitutedor unsubstituted aryl, substituted or unsubstituted heteroaryl,substituted or unsubstituted alkenyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylsulfinyl, substitutedor unsubstituted alkylphosphonyl, substituted or unsubstitutedarylsulfonyl, substituted or unsubstituted arylsulfinyl, substituted orunsubstituted arylphosphonyl;

E2 is of the following formula:

 wherein G′ is selected from the group consisting of substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted aryl;

E3 is of the following formula

 wherein p′″ is between 2 and 200, G″ is Z″ and J′ is independentlyselected from the group consisting of hydrogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted alkoxy, substituted or unsubstituted acyl, substitutedor unsubstituted aroyl, substituted or unsubstituted aryl, substitutedor unsubstituted heteroaryl, substituted or unsubstituted alkenyl,substituted or unsubstituted alkylsulfonyl, substituted or unsubstitutedalkylsulfinyl, substituted or unsubstituted alkylphosphonyl, substitutedor unsubstituted arylsulfonyl, substituted or unsubstitutedarylsulfinyl, substituted or unsubstituted arylphosphonyl or is joinedto G″ so as to form a 5-8 membered ring; and

E4 is of the following formula

 wherein p′″ is between 2 and 200 and G′″ is Z″.

The present invention is also directed to polymers made by the processof the current invention. One of the embodiment is the polymer is of thefollowing formula:

where n is a positive integer in the range of from 1 to 100,000 andwherein A is of the following formula:

when D is D1 and E is Z′;

A is of the following formula:

when D is D2 and E is E1; or

A is of the following formula:

when D is D2 and E is E2; and

and Q″ is a repeat unit derived from a monomer selected from the groupconsisting of maleic anhydride, N-alkylmaleimide, N-arylmaleimide,dialkyl fumarate, cyclopolymerizable monomer, a ring opening monomer, amacromonomer, a vinyl monomer of the following formula:

and a combination thereof;

wherein L is selected from the group consisting of hydrogen, halogen,and substituted or unsubstituted C₁-C₄ alkyl, said alkyl substituentsbeing independently selected from the group consisting of hydroxy,alkoxy, OR″, CO₂H, O₂CR″, CO₂R″ and a combination thereof; and

wherein M is selected from the group consisting of hydrogen, R″, CO₂H,CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″, OR″, and halogen.

Another embodiment is the polymer comprising a mixture of isomers of thefollowing formula:

where n is a positive integer in the range of from 1 to 100,000, D isD3, E is Z, E1 or E2.

Still another embodiment is the polymer is of the following formula:

where n is a positive integer in the range of from 1 to 100,000, D isD4, and E is E3.

A further embodiment is the polymer is of the following formulae:

where n is a positive integer in the range of from 1 to 100,000, D isD4, and E is E4.

One of the advantages of the present polymerization system is that bycontrolling the reaction stoichiometry and the degree of conversion ofthe monomers into polymer the process produces polymers of predeterminedmolecular weight and narrow molecular weight distribution over a widerange of monomers and reaction conditions.

Another advantage of the process of the present invention is that bysuccessively adding different monomers to the reaction mixture, blockpolymers of low polydispersity and desired molecular weight can beproduced.

Still another advantage of the process of the present invention is thatit is possible to create polymers having complex structures, such asgraft, star and branched polymers.

Yet another advantage of the present invention is that it is suitablefor carrying out emulsion, solution, or suspension polymerization ineither a batch, semi-batch, continuous or feed mode.

Still another advantage of the present invention is that it is suitablefor producing waterborne polymers that are water soluble or waterdispersible.

Another advantage of the present invention is that it is suitable forproducing solvent borne polymers that are solvent soluble or solventdispersible.

As defined herein:

“Living polymerization” means a process which proceeds by a mechanismwhereby most chains continue to grow throughout the polymerization andwhere further addition of monomer results in continued polymerization(block copolymers can be prepared by sequential monomer addition ofdifferent monomers). The molecular weight is controlled by thestoichiometry of the reaction and narrow molecular weight distributionpolymers can be produced.

“Radical leaving group” means a group attached by a bond capable ofundergoing homolytic scission during a reaction to thereby form a freeradical.

“GPC number average molecular weight” (Mn) means a number averagemolecular weight and “GPC weight average molecular weight” (Mw) means aweight average molecular weight measured by utilizing gel permeationchromatography. A Waters Associates liquid chromatograph equipped withdifferential refractometer and 10⁶, 10⁵, 10⁴, 10³, 500 and 100 ÅUltrastyragel columns was used. Tetrahydrofuran (flow rate of 1.0mL/min) was used as an eluent. The molecular weights were provided aspolystyrene equivalents.

“Polydispersity” (Mw/Mn) means GPC weight average molecular weightdivided by GPC number average molecular weight.

“Addition-fragmentation” is a two-step chain transfer mechanism whereina radical addition is followed by fragmentation to generate new radicalspecies.

“Chain transfer constant” means the ratio of the rate constant for chaintransfer to the rate constant for propagation at zero conversion ofmonomer and CTA. If chain transfer occurs by addition-fragmentation, therate constant for chain transfer (k_(tr)) is defined as follows:$k_{tr} = {k_{add} \times \frac{k_{\beta}}{k_{\text{-}{add}} + k_{\beta}}}$

where k_(add) is the rate constant for addition to the CTA and k_(add)and k_(β) are the rate constants for fragmentation in the reverse andforward directions respectively.

“Polymer chain” means conventional condensation polymers, such aspolyesters [for example, polycaprolactone, poly(ethyleneterephthalate)], polycarbonates, poly(alkylene oxide)s [for example,poly(ethylene oxide), poly(tetramethylene oxide)], nylons, polyurethanesor addition polymers such as those formed by coordination polymerization(for example polyethylene, polypropylene), radical polymerization (forexample poly(meth)acrylates and polystyrenics or anionic polymerization(for example polystyrene, polybutadiene).

“Cyclopolymerizable monomers” means compounds which contain two or moreunsaturated linkages suitably disposed to allow propagation by asequence of intramolecular and intermolecular addition steps leading theincorporation of cyclic units into the polymer backbone. Most compoundsof this class are 1,6-dienes such as—diallylammonium salts (e.g.,diallyldimethylammonium chloride), substituted 1,6-heptadienes (e.g.,6-dicyano-1,6-heptadiene,2,4,4,6-tetrakis(ethoxycarbonyl)-1,6-heptadiene) and monomers of thefollowing generic structure

where substituents K, K′, T, B, B′ are chosen such that the monomerundergoes cyclopolymerization. For example:

B, B′ are independently selected from the group consisting of H, CH₃,CN, CO₂Alkyl, Ph; K, K′ are selected from the group consisting of CH₂,C═O, Si(CH₃)₂, O; T is selected from the group consisting of C(E)₂, O,N(Alkyl)₂ salts, P(Alkyl)₂ salts, P(O)Alkyl. Additional monomers listedin Moad and Solomon “The Chemistry of Free Radical Polymerization”,Pergamon, London, 1995, pp 162-170, are also suitable.

“Ring opening monomers” are monomers which contain a suitably disposedcarbocyclic or heterocyclic ring to allow propagation by a sequence ofintermolecular addition and intramolecular ring opening steps such asthose described in Moad and Solomon “The Chemistry of Free RadicalPolymerization”, Pergamon, London, 1995, pp 171-186.

“Organometallic species” means a moiety containing one or more metalatoms from Groups m and IV of the Periodic Table and transition elementsand organic ligands, preferably species, such as, Si(X)₃, Ge(X)₃ andSn(X)₃ which provide radical leaving groups and initiate polymerization,X being a group discussed later in the specification.

“Heterocyclic” or “heterocyclyl” means a ring structure containing 3 to18 atoms at least one of which is selected from O, N and S, which may ormay not be aromatic. Examples of “heterocyclyl” moieties are pyridyl,furanyl, thienyl, piperidinyl, pyrrolidinyl, pyrazoyl, benzthiazolyl,indolyl, benzofuranyl, benzothiophenyl, pyrazinyl, and quinolyl,optionally substituted with one or more of alkyl, haloalkyl and halogroups.

“Substituent functionality derived from a substituted or unsubstitutedheterocycle attached via a nitrogen atom” means the group formed byexcising monovalent nitrogen (e.g. >NH) from an appropriate nitrogencontaining heterocycle. Said heterocycles include pyrrolidine, pyrrole,indole, imidazole, carbazole, benzimidazole, benzotriazole, piperidineand isatin, all of which may be substituted or unsubstituted. Forexample, in the case of pyrrole, the substituent functionality is1,3-butadiene-1,4-diyl, and in the case of pyrrolidine it isbutane-1,4-diyl.

Unless specified otherwise, alkyl groups referred to in thisspecification may be branched or unbranched and contain from 1 to 18carbon atoms. Alkenyl groups may be branched or unbranched and containfrom 2 to 18 carbon atoms. Saturated or unsaturated or carbocyclic orheterocyclic rings may contain from 3 to 18 atoms. Aromatic carbocyclicor heterocyclic rings may contain 5 to 18 carbon atoms.

“Conjugating group” is one which provides orbital overlap between theC═S double bond and the lone pair of the S—R group, in the case ofcompounds of formula 2 described below, where D=D1, or to the nitrogenlone pair in the case of compounds of the formula 2, where D=D2, E=E1thereby providing for delocalization of the associated electrons.Examples of such conjugating groups are provided in the subsequent text.

“Substituted” means that a group may be substituted with one or moregroups that are independently selected from the group that consisting ofalkyl, aryl, epoxy, hydroxy, alkoxy, oxo, acyl, acyloxy, carboxy,carboxylate, sulfonic acid, sulfonate, alkoxy- or aryloxy-carbonyl,isocyanato, cyano, silyl, halo, dialkylamino, and amido. Allsubstituents are chosen such that there is no substantial adverseinteraction under the conditions of the experiment.

We have discovered a novel free radical polymerization process and novelpolymers produced therefrom. The process is directed to polymerizing amonomer mix in the presence of a source of free radicals and at leastone of certain sulfur based CTAs chosen so as to confer livingcharacteristics. By utilizing these CTAs, polymers of controlledmolecular weight and low polydispersity can be obtained.

The sulfur based CTAs suitable for use in the present invention have achain transfer constants in the range of from 0.1 to 5000, preferably inthe range of from 1 to 2000 and more preferably in the range of from 10to 500. If the chain transfer constant of the CTA exceeds the upperlimit of the range substantially no polymerization occurs, if it fallsbelow the lower limit it is not possible to produce polymers having lowpolydispersity. The CTAs of the present invention generally should notcopolymerize with monomers during the polymerization process. As aresult, low polydispersity polymers based on monosubstituted monomers(e.g., acrylic monomers, styrene) can be made under a wide range ofreaction conditions.

The sulfur based CTA suitable for use in the present process is of theformula 2 below:

wherein when D is D1 of the following formula 3 below:

then p is in the range of from 1 to 200, E is Z′ and said transfer agentis of the following formula 4 below:

wherein when D is D2 of the following formula 5 below:

then p is in the range of from 1 to 200, E is E1 or E2 and said transferagent is of the following formula 6 below:

wherein when D is D3 of the following formula 7 below:

then p′ is in the range of from 2 to 200, E is Z, E1 or E2 and saidtransfer agent is of the following formula 8 below:

wherein when D is D4 of the following formula 9 below:

—S—R′  (9)

then E is E3 or E4 and said transfer agent is of the following formula10:

 where in all of the above:

R is a p-valent moiety derived from a moiety selected from the groupconsisting of a substituted or unsubstituted alkane, substituted orunsubstituted alkene, substituted or unsubstituted arene, unsaturated oraromatic carbocyclic ring, unsaturated or saturated heterocyclic ring,an organometallic species, and a polymer chain, R. being a free radicalleaving group resulting from R that initiates free radicalpolymerization;

R* and R′ are monovalent moieties independently selected from the groupconsisting of a substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl, unsaturated oraromatic carbocyclic ring, unsaturated or saturated heterocyclic ring,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxy, substituted or unsubstituted dialkylamino, an organometallicspecies, and a polymer chain, R*. being a free radical leaving groupresulting from R* that initiates free radical polymerization;

X is selected from the group consisting of a substituted orunsubstituted methine, nitrogen, and a conjugating group;

Z′ is selected from the group consisting of E1, E2, halogen, substitutedor unsubstituted alkyl, substituted or unsubstituted alkenyl,substituted or unsubstituted aryl, substituted or unsubstitutedheterocyclyl, substituted or unsubstituted alkylthio, substituted orunsubstituted alkoxycarbonyl, substituted or unsubstituted —COOR″,carboxy, substituted or unsubstituted —CONR″₂, cyano, —P(═O)(OR″)₂,—P(═O)R″₂;

R″ is selected from the group consisting of substituted or unsubstitutedalkyl, substituted or unsubstituted alkenyl, substituted orunsubstituted aryl, substituted or unsubstituted heterocyclyl,substituted or unsubstituted aralkyl, substituted or unsubstitutedalkaryl, and a combination thereof;

Z″ is a p′-valent moiety derived from a moiety selected from the groupconsisting of a substituted or unsubstituted alkane, substituted orunsubstituted alkene, substituted or unsubstituted arene, substituted orunsubstituted heterocycle, a polymer chain, an organometallic species,and a combination thereof;

Z is selected from the group consisting of a halogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted aryl, substituted or unsubstituted heterocyclyl,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxycarbonyl, substituted or unsubstituted —COOR″, carboxy,substituted or unsubstituted —CONR″₂, cyano, —P(═O)(OR″)₂, —P(═O)R″₂;

E1 is a substituent functionality derived from a substituted orunsubstituted heterocycle attached via a nitrogen atom, or is of thefollowing formula 11:

 wherein G and J are independently selected from the group consisting ofhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkoxy, substitutedor unsubstituted acyl, substituted or unsubstituted aroyl, substitutedor unsubstituted aryl, substituted or unsubstituted heteroaryl,substituted or unsubstituted alkenyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylsulfinyl, substitutedor unsubstituted alkylphosphonyl, substituted or unsubstitutedarylsulfonyl, substituted or unsubstituted arylsulfinyl, substituted orunsubstituted arylphosphonyl; and

E2 is of the following formula 12:

 wherein G′ is selected from the group consisting of substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted aryl;

E3 is of the following formula 13:

 wherein p′″ is between 2 and 200, G″ is Z″ and J′ is independentlyselected from the group consisting of hydrogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted alkoxy, substituted or unsubstituted acyl, substitutedor unsubstituted aroyl, substituted or unsubstituted aryl, substitutedor unsubstituted heteroaryl, substituted or unsubstituted alkenyl,substituted or unsubstituted alkylsulfonyl, substituted or unsubstitutedalkylsulfinyl, substituted or unsubstituted alkylphosphonyl, substitutedor unsubstituted arylsulfonyl, substituted or unsubstitutedarylsulfinyl, substituted or unsubstituted arylphosphonyl; and

E4 is of the following formula 14:

 wherein p′″ is between 2 and 200 and G′″ is Z′.

The foregoing CTAs are prepared by the following processes:

Vinylogous dithioesters may be prepared in several ways. For example,3-benzylthio-5,5-dimethylcyclohex-2-ene-1-thione is made by a multi-stepprocess. First, piperidine is condensed with5,5-dimethylcyclohexane-1,3-dione in the presence of a strong acid toform enaminoketone, which is then converted to a thione derivative.After the addition of benzyl chloride and hydrogen sulfide work-up, the3-benzylthio-5,5-dimethylcyclohex-2-ene-1-thione is isolated as a purpleoil.

The preparation of benzyl 3,3-di(benzylthio)prop-2-enedithioate, anothervinylogous dithioester, starts with addition of two moles of carbondisulfide to one mole of the Grignard reagent, such as, methyl magnesiumchloride. Treatment with strong base at low temperature followed byaddition of benzyl chloride results in the dithioate, which is an orangesolid.

The thiocarbonylthio compounds with alpha-nitrogen atoms are synthesizedfrom the corresponding nitrogen compounds. For example, benzyl1-pyrrolecarbodithioate is prepared by adding pyrrole to sodium hydridesuspension in dimethyl sulfoxide followed by the addition of carbondisulfide. Benzyl chloride is added and the product, benzyl1-pyrrolecarbodithioate, is isolated by extraction with diethyl ether.

The corresponding 2-pyrrolidineone derivative is prepared in a similarmanner by starting with pyrrolidone instead of pyrrole.

Benzyl (1,2-benzenedicarboximido)carbodithioate is prepared by carbondisulfide addition to potassium phthalimide. Benzyl chloride is thenadded to complete the synthesis.

Bis(thiocarbonyl) disulfides masy be the starting material for otherdithioate compounds. 2,2′-azobis(2-cyanopropane) is thermally decomposedin the presence of pyrrole N-thiocarbonyl disulfide to produce2-cyanoprop-2-yl 1-pyrrolecarbodithioate. 2-Cyanobut-2-yl1-pyrrolecarbodithioate is prepared by the same method using2,2′-azobis(2-cyanobutane) and pyrrole N-thiocarbonyl disulfide.

Benzyl 1-imidazolecarbodithioate may be prepared by yet another method.Benzyl mercaptan is added to a solution of thiocarbonyldiimidazole indichloromethane. The compound is then isolated as a yellow oil.

The Xanthate derivatives may be prepared by adding the correspondinghalocompound to potassium O-ethyl dithiocarbonate. Therefore, O-ethylS-(1-phenylethyl)xanthate is made by adding 1-(bromoethyl)benzene topotassium O-ethyl dithiocarbonate. O-Ethyl S-(2-ethoxycarbonylprop-2-yl)xanthate is made by adding 2-bromoisobutyrate to potassium O-ethyldithiocarbonate, and O-ethyl S-(2-cyanoisopropyl)xanthate is made byadding 2-bromoisobutyronitrile to potassium O-ethyl dithiocarbonate.

Some of the preferred CTAs include the following:

1. The CTA which includes D1 of the formula 15 below:

 when E1 is of the formula 16 below:

2. The CTA which includes D2 of the formula 17 below:

 when E1 is of the formulas 18-20 below:

 or E2 is of the formulas 21 or 22 below:

3. The CTA which includes D2 of the formulas 23 or 24 below:

 when E1 is of the formula 25 below:

4. The CTA which includes D2 of the formulas 26, 27 or 28 below:

 when E2 is of the formula 29 below:

—O—C₂H₅  (29)

If desired, the CTA of the formula 2 further includes a cyclic structurewhen D is D1 and Z′ and E are such that E—C—X=C—Z′ forms a ringstructure. The bridging functionality forms a bridge between Z′ and E.When such as a cyclic structure is present, Z′ and E may not be halogen,methyl or carboxy functionality.

One of the CTAs having the bridging functionality is of the followingformula 30 below where E, Z′=neopentylene:

The source of free radicals suitable for use in the present inventionincludes those compounds that provide free radicals that add to monomersto produce propagating radicals. Propagating radicals are radicalspecies that have added one or more monomer units and are capable ofadding further monomer units.

The amount of the free radical initiator used depends upon the desiredpolydispersity, molecular weight and polymer structure of the resultingpolymer. However, generally less than 10 percent, preferably in therange of from 0.001 to 5 percent of the free radical initiator is used,all percentages being in weight percent based on the total amount ofmonomer mixture.

The source of initiating radicals may be any suitable method ofgenerating free radicals that provide free radicals that add to monomersto produce propagating radicals. This includes such sources as thethermally induced homolytic scission of a suitable compound(s) (such asperoxides, peroxyesters, or azo compounds), the spontaneous generationfrom monomer (e.g. styrene), redox initiating systems, photochemicalinitiating systems or high energy radiation such as electron beam, X- orγ-radiation. The initiating system is chosen such that under thereaction conditions there is no substantial adverse interaction of theinitiator or the initiating radicals with the transfer agent under theconditions of the experiment. The initiator should also have therequisite solubility in the reaction medium or monomer mixture.

Examples of suitable sources of free radicals for the process includeazo compounds and peroxides such as:

2,2′-azobis(isobutyronitrile), 2,2′-azobis(2-cyano-2-butane), dimethyl2,2′-azobis(methyl isobutyrate), 4,4′-azobis(4-cyanopentanoic acid),4,4′-azobis(4-cyanopentan-1-ol), 1,1′-azobis(cyclohexanecarbonitrile),2-(t-butylazo)-2-cyanopropane,2,2′-azobis[2-methyl-N-(1,1)-bis(hydoxymethyl)-2-hydroxyethyl]propionamide,2,2′-azobis[2-methyl-N-hydroxyethyl)]-propionamide,2,2′-azobis(N,N′-dimethyleneisobutyramidine)dihydrochloride,2,2′-azobis(2-amidinopropane)dihydrochloride,2,2′-azobis(N,N′-dimethyleneisobutyramine),2,2′-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide),2,2′-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide),2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],2,2′-azobis(isobutyramide)dihydrate,2,2′-azobis(2,2,4-trimethylpentane), 2,2′-azobis(2-methylpropane),t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctoate,t-butyl peroxyneodecanoate, t-butylperoxy isobutyrate, t-amylperoxypivalate, t-butyl peroxypivalate, di-isopropyl peroxydicarbonate,dicyclohexyl peroxydicarbonate, dicumyl peroxide, dibenzoyl peroxide,dilauroyl peroxide, potassium peroxydisulfate, ammonium peroxydisulfate,di-t-butyl hyponitrite, or dicumyl hyponitrite.

Free radicals may also be generated thermally from the monomer (e.g.styrene), by photochemistry, from redox initiation systems or by acombination of these methods.

Photochemical initiator systems are chosen to have the requisitesolubility in the reaction medium or monomer mixture and have anappropriate quantum yield for radical production under the conditions ofthe polymerization. Examples include benzoin derivatives, benzophenone,acyl phosphine oxides, and photo-redox systems. Such processes wherefree radicals are derived by direct photolysis of the compound offormula 2 where D=D2 and E=E1 or E2 are not part of this invention.

Redox initiator systems are chosen to have the requisite solubility inthe reaction medium or monomer mixture and have an appropriate rate ofradical production under the conditions of the polymerization; theseinitiating systems may include combinations of the following oxidantsand reductants:

oxidants: potassium peroxydisulfate, hydrogen peroxide, t-butylhydroperoxide.

reductants: iron (II), titanium (III), potassium thiosulfite, potassiumbisulfite other suitable initiating systems are described in recenttexts. See, for example, Moad and Solomon “The Chemistry of Free RadicalPolymerization”, Pergamon, London, 1995, pp 53-95.

A monomer mix suitable for use in the present invention may include atleast one vinyl monomer of the formula 31 below:

where L is selected from the group consisting of hydrogen, halogen, andsubstituted or unsubstituted C₁-C₄ alkyl, said alkyl substituents beingindependently selected from the group consisting of OH, OR″, CO₂H,O₂CR″, CO₂R″ and a combination thereof;

where M in the formula 31 is selected from the group consisting ofhydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″, OR″,and halogen.

R″ is as defined above.

Depending upon the type of polymer desired, the monomer mix may alsoinclude the following monomers:

Maleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate,cyclopolymerizable or a ring opening monomer, or a combination thereof.The monomer mix may also include macromonomers, which are compounds ofthe formula 31 where L or M is a polymer chain.

The monomers or comonomers of the formula 31 generally include one ormore of acrylate and methacrylate esters, acrylic and methacrylic acids,styrene, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile,vinyl esters and mixtures of these monomers, and mixtures of thesemonomers with other monomers. As one skilled in the art would recognize,the choice of comonomers is determined by their steric and electronicproperties. The factors which determine copolymerizability of variousmonomers are well documented in the art. For example, see: Greenley, R.Z. in Polymer Handbook 3rd Edition (Brandup, J., and Immergut, E. HEds.) Wiley: New York, 1989 p II/53.

The specific monomers or comonomers of the formula 31 include one ormore of the following:

methyl methacrylate, ethyl methacrylate, propyl methacrylate (allisomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate,isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenylmethacrylate, methacrylonitrile, alpha-methylstyrene, methyl acrylate,ethyl acrylate, propyl acrylate (all isomers), butyl acrylate (allisomers), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid,benzyl acrylate, phenyl acrylate, acrylonitrile, styrene, functionalmethacrylates, acrylates and styrenes selected from glycidylmethacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate(all isomers), hydroxybutyl methacrylate (all isomers), methylα-hydroxymethyacrylate, ethyl α-hydroxymethyacrylate, butylα-hydroxymethyacrylate, N,N-dimethylaminoethyl methacrylate,N,N-diethylaminoethyl methacrylate, triethyleneglycol methacrylate,itaconic anhydride, itaconic acid, glycidyl acrylate, 2-hydroxyethylacrylate, hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate(all isomers), N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethylacrylate, triethyleneglycol acrylate, methacrylamide,N-methylacrylamide, N,N-dimethylacrylamide, N-tert-butylmethacrylamide,N-n-butylmethacrylamide, N-methylolmethacrylamide,N-ethylolmethacrylamide, N-tert-butylacrylamide, N-n-butylacrylamide,N-methylolacrylamide, N-ethylolacrylamide, vinyl benzoic acid (allisomers), diethylaminostyrene (all isomers), alpha-methylvinyl benzoicacid (all isomers), diethylamino alpha-methylstyrene (all isomers).p-vinylbenzene sulfonic acid, p-vinylbenzene sulfonic sodium salt,trimethoxysilylpropyl methacrylate, triethoxysilylpropyl methacrylate,tributoxysilylpropyl methacrylate, dimethoxymethylsilylpropylmethacrylate, diethoxymethylsilylpropylmethacrylate,dibutoxymethylsilylpropyl methacrylate, diisopropoxymethylsilylpropylmethacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropylmethacrylate, dibutoxysilylpropyl methacrylate, diisopropoxysilylpropylmethacrylate, trimethoxysilylpropyl acrylate, triethoxysilylpropylacrylate, tributoxysilylpropyl acrylate, dimethoxymethylsilylpropylacrylate, diethoxymethylsilylpropyl acrylate, dibutoxymethylsilylpropylacrylate, diisopropoxymethylsilylpropyl acrylate, dimethoxysilylpropylacrylate, diethoxysilylpropyl acrylate, dibutoxysilylpropyl acrylate,diisopropoxysilylpropyl acrylate, vinyl acetate, vinyl butyrate, vinylbenzoate, vinyl chloride, vinyl fluoride, vinyl bromide, maleicanhydride, N-phenylmaleimide, N-butylmaleimide, N-vinylpyrrolidone,N-vinylcarbazole, butadiene, isoprene, chloroprene, ethylene andpropylene.

Other suitable monomers include cyclopolymerizable monomers such asthose disclosed in International Patent Application PCT/AU94/00433 orMoad and Solomon “The Chemistry of Free Radical Polymerization”,Pergamon, London, 1995, pp 162-171 and ring opening monomers such asthose described in Moad and Solomon “The Chemistry of Free RadicalPolymerization”, Pergamon, London, 1995, pages 171-186.

The polymer resulting from the process of the present invention is ofthe following formula 32:

where n is a positive integer in the range of from 1 to 100,000,preferably in the range of from 5 to 10000 and more preferably in therange of from 10 to 1000. Q″ in the formula 32 and the formulas below isa repeat unit derived from a monomer selected the group consisting ofmaleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate,cyclopolymerizable monomer, a ring opening monomer, a macromonomer, avinyl monomer of formula 31 (when Q″ will have structure (33)

and a combination thereof;

wherein L is selected from the group consisting of hydrogen, halogen,and substituted or unsubstituted C₁-C₄ alkyl, said alkyl substituentsbeing independently selected from the group consisting of OH, OR″, CO₂H,O₂CR″, CO₂R″ and a combination thereof;

wherein M is selected from the group consisting of hydrogen, R″, CO₂H,CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″, OR″, and halogen; and

R″ is as defined above.

A in the formula 32 is of the formula 34 below, when D is D1 and E isZ′:

Thus, when p=1 the resulting polymer will comprise a mixture of theisomers shown in formula 35 below:

Alternatively, A is of the formula 36 below when D is D2 and E is E1:

Thus, when p=1, the resulting polymer is of the formula 37 below:

In yet another embodiment, A is of the formula 38 below when D is D2 andE is E2:

Thus, when p=1, the resulting polymer is of the formula 39 below:

Another type of polymer resulting from the process of invention has thefollowing formula 40 (the product will be a mixture of isomers).:

where n is a positive integer in the range of from 1 to 100,000, and Dis D3 and E is Z, E1 or E2.

Still other types of polymer resulting from the process of invention hasthe formula 41 or 41a:

where n is a positive integer in the range of from 1 to 100,000, and Dis D4 and E is E3.

where n is a positive integer in the range of from 1 to 100,000, and Dis D4 and E is E4.

In the context of the present invention, low polydispersity polymers arethose with polydispersities that are significantly less than thoseproduced by conventional free radical polymerization. In conventionalfree radical polymerization, polydispersities of the polymers formed aretypically in the range 1.5 to 2.0 at low monomer conversions in therange of from 0.1% to 10% and are substantially greater in the range offrom 2 to 10 at higher monomer conversions in the range of from 10% to100%. Polymers having low polydispersity in the range of from 1.05 to1.5 are preferred. Those having the polydispersity in the range of 1.05to 1.3 are more preferred. Moreover, one of the significant advantagesof the process of the present invention is that the foregoing lowpolydispersity can be maintained even at high monomer conversions of inthe range of from 10% to 100%.

However, it should be understood, it is also possible, if desired, toproduce polymers with broad, yet controlled, polydispersity ormultimodal molecular weight distribution by controlled addition of theCTA over the course of the polymerization process of the presentinvention.

The invention can be used to narrow the polydispersity of polymersformed in polymerizations that would otherwise produce polymers of broador very broad polydispersities. In this circumstance a preferredpolydispersity is one which is less than that formed in the absence ofthe CTA.

While not wishing to be limited to any particular mechanism, it isbelieved that the mechanism of the process is as summarized in Scheme Ibelow. Propagating radicals P_(n). are produced by radicalpolymerization. These can react reversibly with the chain transfer agentRA to form an intermediate radical P_(n)A(.)R which fragments to give aradical R. (which adds monomer to reinitiate polymerization) and a newtransfer agent P_(n)A. This new transfer agent P_(n)A has similarcharacteristics to the original transfer agent RA in that it reacts withanother propagating radical P_(m). to form an intermediate radicalP_(n)A(.)P_(m) which fragments to regenerate P_(n). and form a newtransfer agent P_(m)A which has similar characteristics to RA. Thisprocess provides a mechanism for chain equilibration and accounts forthe polymerization having living characteristics.

P_(n). and P_(m). are propagating radicals of chain length n and mrespectively. R. is a chain transfer agent derived radical which caninitiate polymerization to produce a new propagating radical. RA, P_(n)Aand P_(m)A are CTAs.

The molecular weight and the polydispersity of the polymer made by theprocess of the present invention are controlled by one or more of thefollowing:

The polymerization conditions are selected to minimize the number ofchains formed from initiator-derived radicals to an extent consistentwith obtaining an acceptable rate of polymerization. Termination ofpolymerization by radical-radical reaction will lead to chains whichcontain no active group and therefore cannot be reactivated. The rate ofradical-radical termination is proportional to the square of the radicalconcentration. Furthermore, in the synthesis of block, star or branchedpolymers, chains formed from initiator-derived radicals will constitutea linear homopolymer impurity in the final product. These reactionconditions therefore require careful choice of the initiatorconcentration and, where appropriate, the rate of the initiator feed.

It is also desirable to choose other components of the polymerizationmedium (for example, the solvents, surfactants, additives, andinitiator) such that they have a low transfer constant towards thepropagating radical. Chain transfer to these species will lead to theformation of chains which do not contain the active group.

As a general guide in choosing conditions for the polymerization ofnarrow polydispersity polymers, the concentration of initiator(s) andother reaction conditions [solvent(s) if any, reaction temperature,reaction pressure, surfactants if any, other additives] should be chosensuch that the molecular weight of polymer formed in the absence of theCTA is at least twice that formed in its presence. In polymerizationswhere radical-radical termination is solely by disproportionation, thisequates to choosing an initiator concentration such that the total molesof initiating radicals formed during the polymerization is in the rangeof 0.000001 times to 0.5 times that of the total moles of CTA. Morepreferably, conditions should be chosen such that the molecular weightof polymer formed in the absence of the CTA is at least 5-fold thatformed in its presence ([initiating radicals]/[CTA]<0.2).

Thus, by varying the ratio of the total number of moles of the CTA tothe total number of moles of the free radical initiator added to apolymerization medium, the polydispersity of the resulting polymer iscontrolled. Thus, by decreasing the foregoing ratio, a polymer of lowerpolydispersity is obtained and by increasing the ratio, a polymer ofhigher polydispersity is obtained.

With these provisos, the polymerization process according to the presentinvention is performed under the conditions typical of conventionalfree-radical polymerization. Polymerization employing the CTAs of thepresent invention is suitably carried out with temperatures during thereaction in the range −20° C. to 200° C., preferably in the range 40 to160° C.

Unlike, a conventional free radical polymerization process, themolecular weight of the resulting polymer by the process of the presentinvention generally increases in a predictable and linear fashion, andmay be estimated in accordance with the following relationship:${MW}_{prod} = {{\frac{\lbrack {{Moles}\quad {of}\quad {monomer}\quad {consumed}} \rbrack}{\lbrack {{moles}\quad {of}\quad {CTA}} \rbrack} \times {MW}_{mon}} + {MW}_{cta}}$

where MW_(prod) is the number average molecular weight of the isolatedpolymer, MW_(mon) is the molecular weight of the monomer and MW_(cta) isthe molecular weight of the CTA. The foregoing expression applies underreaction conditions where the number of initiator-derived chains is lessthan 10 percent with respect to total chains and when the added CTA iscompletely reacted. More complex expressions may be derived to enableprediction of the molecular weight in other circumstances.

By way of illustration, consider the data provided in Examples 19 and20. A close correspondence is seen between molecular weights calculatedaccording to the above equation and those found experimentally.

moles MW prod fractional monomer MW prod (found) conversion consumedmoles CTA (calc) 37257 0.31000 0.017230 4.0952e-05 36393 97127 0.890000.049467 4.0952e-05 104090 110910 0.91000 0.050579 4.0952e-05 1064303381.0 0.22000 0.012228 0.00040952 2777.9 5952.0 0.47000 0.0261230.00040952 5695.9 8762.0 0.74000 0.041130 0.00040952 8847.4

The process of this invention can be carried out in emulsion, solutionor suspension in either a batch, semi-batch, continuous, or feed mode.Otherwise-conventional procedures can be used to produce narrowpolydispersity polymers. For lowest polydispersity polymers, the CTA isadded before polymerization is commenced. For example, when carried outin batch mode in solution, the reactor is typically charged with CTA andmonomer or medium plus monomer. To the mixture is then added the desiredamount of initiator and the mixture is heated for a time which isdictated by the desired conversion and molecular weight.

Polymers with broad, yet controlled, polydispersity or with multimodalmolecular weight distribution can be produced by controlled addition ofthe CTA over the course of the polymerization process.

In the case of emulsion or suspension polymerization the polymerizationmedium will often be predominantly water and the conventionalstabilizers, dispersants and other additives can be present.

For solution polymerization, the polymerization medium can be chosenfrom a wide range of media to suit the monomer(s) being used. Forexample, aromatic hydrocarbons, such as, petroleum naphtha or xylenes;ketones, such as, methyl amyl ketone, methyl isobutyl ketone, methylethyl ketone or acetone; esters, such as, butyl acetate or hexylacetate; and glycol ether esters, such as, propylene glycol monomethylether acetate.

As has already been stated, the use of feed polymerization conditionsallows the use of CTAs with lower transfer constants and allows thesynthesis of polymers that are not readily achieved using batchpolymerization processes. If the polymerization is carried out as a feedsystem the reaction can be carried out as follows. The reactor ischarged with the chosen polymerization medium, the CTA and optionally aportion of the monomer mixture. Into a separate vessel is placed theremaining monomer mixture. The free radical initiator is dissolved orsuspended in polymerization medium in another separate vessel. Themedium in the reactor is heated and stirred while the monomermixture+medium and initiator+medium are introduced, for example by asyringe pump or other pumping device. The rate and duration of feed isdetermined largely by the quantity of solution, the desiredmonomer/CTA/initiator ratio and the rate of the polymerization. When thefeed is complete, heating may be continued for an additional period.Sequential addition of different monomers will give a block or gradientcopolymer.

Following completion of the polymerization, the polymer can be isolatedby stripping off the medium and unreacted monomer(s) or by precipitationwith a non-solvent. Alternatively, the polymer solution/emulsion can beused as such, if appropriate to its application.

The process of the present invention is compatible with a wide varietyof monomers and can be used under varied reaction conditions to producepolymers having low polydispersity. By varying the rate of monomer(s)addition or by varying the sequence in which the monomer(s) may be addedto the polymerization medium, the process present invention may be usedto produce block and multi-block and gradient polymers. By selecting thefunctionalities desired, an end-functional polymer of specific endfunctionalities can be readily produced.

Examples of CTAs of the formula 6 which are precursors to graft polymersof formula 32, which include copolymers and/or xanthate ordithiocarbamate derivative of the following formula 42:

when in the formula 32, p=n and R is of the following formula 43:

Examples of CTAs containing functionality attached to a common nucleusare described below.

When in the formula 6 p=2, R=p-xylylene, the CTA is of the formula 44below:

and when in the formula 10, p′″=2, E=E4, G′″ =p-phenylene then the CTAis of the formula 45 below:

The compound of the following formula (46) will provide a star polymer,as shown below:

When in the formula 6, p=4 and R is of the following formula 47 below:

The polydispersity obtained under a given set of reaction conditions issensitive to the value of the transfer constant (C_(tr)). Lowerpolydispersities will result from the use of CTAs with higher transferconstants. According to the above mechanism, the chain transferactivities of the reagents (RA, P_(n)A and P_(m)A) will be determined bythe reactivity of the C═S double bond and by the rate of fragmentationand the partitioning of the intermediate radicals between startingmaterials and products.

Müller et al. have derived relationships which enable polydispersitiesto be estimated for polymerizations which involve chain equilibration byreversible chain transfer (Miller, A. H. E.; Zhuang, R.; Yan, D.;Litvenko, G. Macromolecules, 28, 4326 (1995))

M_(w)/M_(n)=1+1/C_(tr)

Where C_(tr) is the chain transfer constant.

This above relationship should apply to batch polymerizations carried tofull conversion in the situation where the number of initiator-radicalderived chains is small with respect to total chains and there are noside reactions. This relationship suggests that the transfer constantshould be greater than 2 to obtain a polydispersity <1.5 in a batchpolymerization.

For a feed polymerization in which the monomer concentration is keptconstant by continual replenishment, Miller et al. suggest that thefollowing relationship should hold (Müller, A. H. E.; Litvenko, G.,Macromolecules 30, 1253 (1997)):

Mw/Mn=1+(2/DPn)(1/C_(tr))([M]/[CTA])

Where C_(tr) is the chain transfer constant and DPn is the degree ofpolymerization of the product.

A possible mechanism of the addition-fragmentation step, withoutreliance thereon, for the case of compounds of the formula 2 where D isD1 is as follows:

The foregoing proposed mechanism is in accord with experimentalobservations. According to this mechanism, the X group may in principlebe any group which maintains conjugation between the C═S and the S—Rgroups. Some possible structures are included in the following formulas48-50:

Other examples of CTAs with conjugating groups are of the followingformulas 51-53 below:

Structures containing multiple alkylthio groups allow the synthesis ofpolymers of more complex architecture. For example the followingcompound can give rise to a three arm star 54 as follows:

Sequential addition of monomers will give rise to block copolymers.

It will be clear to those skilled in the art that to be effective as aCTA in the present invention, the group R of the CTA must be both a freeradical leaving group and a species that initiates free radicalpolymerization. Leaving group ability is determined both by stericfactors and by radical stability. Examples of preferred R groups for theCTA are benzyl derivatives (—CR′″₂Ph) and cyanoalkyl derivatives(—CR′″₂CN) and other moieties known to the art as free radical leavinggroups.

The leaving group ability of R. will also be determined by the nature ofthe propagating species formed in the polymerization. For example, instyrene polymerization, R is preferably selected from the groupconsisting of benzyl, 1-phenylethyl, 2-phenylpropyl,2-(alkoxycarbonyl)prop-2-yl, 2-cyanoprop-2-yl, 2-cyanobut-2-yl, and1-cyanocyclohexyl. In methyl methacrylate polymerization R ispreferrably selected from the group consisting of 2-phenylpropyl,2-cyanoprop-2-yl, 2-cyanobut-2-yl, and 1-cyanocyclohexyl. In vinylacetate polymerization R is preferrably selected from the groupconsisting of 2-(alkoxycarbonyl)prop-2-yl, cyanomethyl,2-cyanoprop-2-yl, 2-cyanobut-2-yl, and 1-cyanocyclohexyl.

To avoid retardation the R′″, substituents should be chosen such that R.gives facile addition to the monomer. In this context, the preferred R′″groups are independently selected from the group consisting of hydrogenand substituted alkyl. The ability of R. to initiate polymerization willbe determined by the nature of the monomers used in the polymerization.In polymerization of styrene and methacrylates benzyl derivatives(—CR′″₂Ph) and cyanoalkyl derivatives (—CR′″₂CN) are effective. However,in vinyl acetate polymerization benzyl derivatives (—CR′″₂Ph) are slowto initiate polymerization, and retardation may be observed, butcyanoalkyl derivatives (—CR′″₂CN) and the corresponding esters(—CR′″₂CO₂Alkyl) are effective.

In polymerizations of (meth)acrylates and styrene, we have discoveredthat dithiocarbamate CTAs (formula 2, D=D2, E=E1) with conjugating orelectron withdrawing substituents at the dithiocarbamate nitrogen aresubstantially more effective than dithiocarbamate derivatives withsimple alkyl substituents.

Thus, the preferred groups in E1 for this application are aromaticnitrogen heterocycles where G—N—J forms part of aromatic cyclic group,such as those of the following formulas 55 and 56 below:

and groups in E1 such as cyclic amides where G—N—J forms part of anon-aromatic cyclic group with substituent such as oxo conjugated tonitrogen as in the following formulas 57-59 below:

One possible explanation for the greater activity of the abovedithiocarbamates is in terms of a higher reactivity of the C═S doublebond towards free radical addition. This is attributed to the effect ofthe conjugating or electron withdrawing substituents giving greaterdouble bond character to the C═S double bond.

In carbamates and amides the N—CO link has partial double bond characteras a result of the delocalisation of the non-bonded nitrogen lone pairwith the p electrons of carbonyl group (Deslongchamps, P.Stereoelectronic effects in organic chemistry, Pergamon Press, NY,1983). As a result, the oxygen of the carbonyl group has a partialnegative charge. Since sulfur has a higher electron affinity thanoxygen, this effect would be expected to be more pronounced indithiocarbamates.

If the nitrogen lone pair participates in an alternate π-system (e.g.the aromatic pyrrole ring) the lone pair will be less available fordelocalization into the thiocarbonyl bond resulting in a greater doublebond character for the C═S double bond and hence a greater reactivity ofthe CTA towards radicals.

Similar considerations apply in the case of xanthate esters. We havefound that effectiveness of xanthate ester CTAs (formula 2, D=D2, E=E2)in providing low polydispersity polymers in acrylate polymerizationincreases in the series where G′ is —OEt<—OC₆H₅<C₆F₅.

The transfer constants of dithiocarbamate and xanthate derivatives(compounds of formula 2 D=D2, E=E1 or E2 repectively) are stronglydependent on the monomer used. Thus dithiocarbamate and xanthatederivatives of formula 2 with D=D2 and E=E1 or E2 wherein G, J, and G′are independently selected from the group consisting of substituted orunsubstituted alkyl, substituted or unsubstituted alkylene, substitutedor unsubstituted aryl, substituted or unsubstituted heterocyclyl haverelatively low transfer constants in polymerization of methacrylate orstyrene monomers and are not effective in giving narrow polydispersitypolymers in batch polymerization of such monomers.

However in polymerization of vinyl acetate, vinyl butyrate, vinylbenzoate, vinyl chloride, vinyl bromide, vinyl fluoride,N-vinylpyrolidone, N-vinylcarbazole and similar vinyl monomers thesedithiocarbamate and xanthate derivatives (compounds of formula 2, D=D2,E=E1 or E2) have higher transfer constants enabling low polydispersitypolymers to be achieved. Preferred CTAs for use with these vinylmonomers include compounds of formula 2 with D=D2 and E=E1 or E2 whereinG, J, and G′ are independently selected from the group consisting ofsubstituted or unsubstituted alkyl,substituted or unsubstitutedalkylene, substituted or unsubstituted aryl, substituted orunsubstituted heterocyclyl, or when E=E1, G-N-J forms part of anon-aromatic cyclic group.

The invention has wide applicability in the field of free radicalpolymerization and can be used to produce polymers that are suitable foruse in compositions for coatings, including automotive OEM andrefinishes, as primers, basecoats, undercoats, overcoats and clearcoats. The polymers are also suitable for use in compositions formaintenance finishes for a wide variety of substrates, such as steel,copper, brass and aluminum or non-metallic substrates, such as, wood,leather and concrete.

A coating composition containing the polymer prepared by the process ofthe present invention may also contain conventional additives, such as,pigments, stabilizers, flow agents, toughening agents, fillers,durability agents, corrosion and oxidation inhibitors, rheology controlagents, metallic flakes and other additives. Such additional additiveswill, of course, depend on the intended use of the coating composition.Fillers, pigments, and other additives that would adversely effect theclarity of the cured coating will not be included if the composition isintended as a clear coating.

Block and star, and branched polymers can be used as compatibilizers,thermoplastic elastomers, dispersing agents, flocculants, surfactants,rheology control agents or as additives to modify the surface propertiesof bulk polymers and plastics. Additional applications for polymers ofthe invention are in the fields of imaging, electronics (e.g.,photoresists), engineering plastics, adhesives, sealants, papercoatings, printing inks, and polymers in general.

The invention can also be applied to the controlled grafting of polymerchains onto solid polymers or surfaces for the purpose of controllingbiocompatibility, biostability, hydrophilicity, hydrophobicity, adhesionor friction.

EXAMPLES

Monomers were purified (to remove inhibitors) and flash distilledimmediately prior to use. Degassing was accomplished by repeatedfreeze-evacuate-thaw cycles. Once degassing was complete ampoules wereflame sealed under vacuum and completely submerged in an oil bath at thespecified temperature for the specified times. The percentageconversions were calculated gravimetrically.

Examples 1-6 illustrate the synthesis of thiocarbonylthio compounds withan α-nitrogen substituent (dithiocarbamates formula 2, D=D2, E=1)

Procedure 1 Preparation of Benzyl 1-Pyrrolecarbodithioate (60)

Pyrrole (1.34 g, 20 mmol) was added dropwise to a stirred suspension ofsodium hydride (0.48 g, 20 mmol) in dimethyl sulfoxide (20 mL). Oncompletion of addition the resulting brown solution was stirred at roomtemperature for 30 minutes before the addition of carbon disulfide (1.52g, 20 mmol). The solution was allowed to stir at room temperature for afurther half hour and benzyl chloride (2.53 g, 20 mmol) added. Water (20mL) was added after 1 hour followed by diethyl ether (20 mL). Theorganic layer was separated and the aqueous layer extracted with diethylether (2×20 mL). The combined extracts were dried with magnesiumsulfate, filtered and the solvent removed. The crude product waschromatographed using 5% ethyl acetate in petroleum spirits to isolatethe product as a yellow oil (2.34 g, 50%). ¹H-nmr (CDCl₃) δ 4.60 (2H),6.30 (2H), 7.40 (5H), 7.70 (2H). ¹³C-nmr (CDCl₃) δ 41.7, 114.2, 120.6,128.0, 128.8, 129.4, 135.0, 189.0.

Example 1 Preparation of Benzyl 1-(2-Pyrrolidinone)carbodithioate (61)

Benzyl chloride (0.8 g, 6.35 mmol) was added to a suspension solution of1-(2-pyrrolidinone)carbodithioc acid (0.97 g, 6.02 mmol) and potassiumcarbonate (0.84 g, 6.09 mmol) in absolute ethanol (10 mL) at roomtemperature. The resulting mixture was stirred at room temperature forthree hours. Water (25 mL) was added, then extracted with ethyl acetate(3×20 mL). The combined organic layer was dried over anhydrous sodiumsulfate. After removal of solvent, the residue was subjected to columnchromatography (Kieselgel-60, 70-230 mesh) using n-hexane initially (toremove unreacted benzyl chloride) and then with ethyl acetate/n-hexane3:7 as eluent. The title compound, benzyl1-(2-pyrrolidinone)carbodithioate (61) (1.1 g, 73%) was obtained as abright yellow solid, m.p. 57-58° C. ¹H-nmr (CDCl₃) δ 2.11 (ddt, 2H),2.73 (t, 2H), 4.25 (dd, 2H), 4.40 (s, 2H) and 7.20-7.40 (m, 5H).

Example 2 Preparation of Benzyl (1,2-Benzenedicarboximido)carbodithioate(62)

Carbon disulfide (1.0 g, 13.1 mmol) was added slowly over ten minutes toa suspension of potassium phthalimide (1.85 g, 10 mmol) in dimethylsulfoxide (20 mL) at room temperature. The resulting mixture was allowedto stir for a further five hours at room temperature before the additionof benzyl chloride (1.26 g, 10 mmol). The mixture was then heated at 50°C. for three hours. Water (30 mL) was added, and the mixture extractedwith ethyl acetate (3×20 mL). The combined organic layer was dried overanhydrous magnesium sulfate, filtered, and removed on a rotaryevaporator to give a yellow oil. The crude reaction mixture waschromatographed (kieselgel-60, 70-230 mesh, ethyl acetate/n-hexane 1:9as eluent) to give benzyl (1,2-benzenedicarboximido)carbodithioate (62)(180 mg, 5.8% yield). ¹H-nmr (CDCl₃) δ 4.55 (s, 2H), 7.30-7.45 (m, 5H),7.82 (dd, 2H) and 7.98 (dd, 2H).

Example 3 Preparation of 2-Cyanoprop-2-yl 1-Pyrrolecarbodithioate (63)

Pyrrole N-thiocarbonyl disulfide (0.15 g, 0.53 mmol) and2,2′-azobis(isobutyronitrile) (0.16 g, 1 mmol) was dissolved in ethylacetate (5 mL) and transfered into a Young's vessel. The contents weredegassed and heated at 70° C. for 24 hours. The solvent was removedunder vacuum and the residue chromatographed on silica (10% ethylacetate/petroleum spirits) to afford 2-cyanoprop-2-yl1-pyrrolecarbodithioate (135 mg, 61%). ¹H-nmr (CDCl₃) δ 1.99 (6H), 6.38(2H), 7.61 (2H). ¹³C-nmr (CDCl₃) δ 27.0, 114.7, 120.7, 176.4, 193.2.

Example 4 Preparation of 2-Cyanobut-2-yl 1-Pyrrolecarbodithioate (64)

Pyrrole N-thiocarbonyl disulfide (0.71 g, 2.5 mmol) and2,2′-azobis(2-cyanobutane) (0.63 g, 3.3 mmol) was dissolved in ethylacetate (10 mL) and transfered into a Young's vessel. The contents weredegassed and heated at 70° C. for 24 hours. The solvent was removedunder vacuum and the residue chromatographed on alumina (activity III)(15% ethyl acetate/petroleum spirits) to afford 2-cyanobut-2-yl1-pyrrolecarbodithioate as an oil (310 mg, 28%). The compound graduallydecomposes at room temperature and needs to be stored in the freezer.¹H-nmr (CDCl₃) δ 1.10 (3H, t,), 1.89 (3H, s), 2.22 (2H, m), 6.30 (2H),7.65 (2H).

Procedure 2 Preparation of Benzyl 1-Imidazolecarbodithioate (65)

Benzyl mercaptan (0.68 g, 5.5 mmol) was added dropwise to a solution ofthiocarbonyl diimidazole (0.89 g, 5 mmol) in dichloromethane (10 mL) atroom temperature. The solution was allowed to stir for 30 minutes at thesame temperature and the solvent was then removed under vacuum. Theresidue was chromatographed (Kieselgel-60, 70-230 mesh) using ethylacetate/petroleum spirits 3:7 as eluent to afford benzyl1-imidazolecarbodithioate (65) (0.78 g, 54%) as a bright yellow solid.¹H-nmr (CDCl₃) δ 4.60 (2H), 7.10 (1H,), 7.40 (5H,), 7.75 (1H), 8.45(1H). ¹³C-nmr (CDCl₃) δ 641.73, 117.6, 131.5, 135.0, 128.3, 128.9,129.4, 133.8, 188.3.

Example 5 Preparation ofN,N-Dimethyl-S-(2-cyanoprop-2-yl)dithiocarbamate (66)

Tetramethylthiuramdisulfide (1.2 g, 5 mmol) and2,2′-azobis(isobutyronitrile) (1.23 g, 7.5 mmol) was dissolved inbenzene. The solution was degassed by bubbling nitrogen through thesolution for 10 minutes and heated at reflux for 24 hours. Benzene wasremoved under reduced presssure and the crude residue chromatographed(silica gel, 30% ethyl acetate in petroleum spirits) to afford the titlecompound (1.74 g, 93%). ¹H-nmr (CDCl₃) δ 1.9 (6H), 3.4 (6H, bd). ¹³C-nmr(CDCl₃) δ 27.4, 42.15, 62.5, 122.0, 190.0.

Procedure 3 Preparation of N,N-Diethyl S-Benzyl Dithiocarbamate (67)

Benzyl bromide (2.05 g, 12 mmol) in THF (10 mL) was added dropwise over15 minutes to a supension of sodium N,N-diethyldithiocarbamatetrihydrate (2.25 g, 10 mmol) in 25 mL of THF at room temperature. Thesolution was allowed to stir at room temperature for 3 hours when thesolids were filtered off and the filtrate concentrated. The cruderesidue was purified by column chromatography (silica gel, 20% ethylacetate in petroleum spirits) to obtain the title compound (2.25 g,94%). ¹H-nmr (CDCl₃) δ 1.3 (6H), 3.7 (2H), 4.1 (2H), 4.6 (2H), 7.3 (5H).

Example 6 Preparation of Cyanomethyl 1-(2-Pyrrolidone)carbodithoate (68)

Chloroacetonitrile (1 mL, 15.9 mmol) was added to a suspension solutionof 1-(2-pyrrolidinone)carbodithioic acid (0.97 g, 6.02 mmol) andpotassium carbonate (0.84 g, 6.09 mmol) in acetonitrile (10 mL) at roomtemperature. The resulting mixture was stirred at room temperature for18 hours. Water (25 mL) was added, then extracted with ethyl acetate(3×20 mL). The combined organic layer was dried over anhydrous sodiumsulfate. After removal of solvent, the residue was subjected to columnchromatography (Kieselgel-60, 70-230 mesh) using ethyl acetate/n-hexane1:4 as eluent. The title compound, cyanomethyl1-(2-pyrrolidinone)carbodithioate (0.74 g, 65.5% yield) was obtained asa yellow solid, m.p. 65-66° C. ¹H-nmr (CDCl₃) δ 2.20 (ddt, 2H), 2.80 (t,2H), 4.00 (s, 2H) and 4.25 (dd, 2H).

Procedure 4 Preparation of N,N-DiethylS-(2-Ethoxycarbonylprop-2-yl)dithiocarbamate (69)

The title compound was prepared according to T. Otsu, T. Matsunaga, T.Doi and A. Matsumoto, Eur. Polym. J. 31, 67-78 (1995).

Examples 6-11 illustrate the synthesis of thiocarbonylthio compoundswith an α-oxygen substituent (xanthate esters formula 2 D=D2, E=E2)

Procedure 5 Preparation of O-Ethyl S-(1-Phenylethyl)xanthtate (70)

A solution of 1-(bromoethyl)benzene (3.7 g) and potassium O-ethyldithiocarbonate (3.2 g) in ethanol (50 mL) was stirred at roomtemperature for 16 hours. The reaction was diluted with water (50 mL)and the organics extracted with n-hexane. The combined organic layerswere washed with water, brine and dried over magnesium sulfate. Thesolvent was evaporated and the title compound was obtained as a yellowoil (4.4 g, 97%).

Example 7 Preparation of O-Ethyl S-(2-(Ethoxycarbonyl)prop-2-yl)xanthate(71)

A solution of 2-bromoisobutyrate (19.5 g) and potassium O-ethyldithiocarbonate (16.0 g) in ethanol (200 mL) were allowed to stir atroom temperature for 20 hours and then at 50° C. for 16 hours. Thereaction was diluted with water (200 mL) and the organics extracted withn-hexane. The combined organic layers were washed with water, brine anddried over anhydrous sodium sulfate. The solvent was evaporated and theresidue purified by column chromatography (Alumina oxide 90 70-230 mesh,Activity II-III) eluting with 1:9 diethyl ether:n-hexane to afford thetitle compound as a yellow oil (40% yield).

Example 8 Preparation of O-Ethyl S-(2-Cyanoprop-2-yl)xanthate (72) fromPotassium O-Ethyl Dithiocarbonate

A solution of bromoisobutyronitrile (10 g) and potassium O-ethyldithiocarbonate (10.84 g) in ethanol (280 g) were heated at 40° C. withstirring for 40 hours. The mixture was then allowed to stir for 12 daysat room temperature. The reaction mixture was diluted with water (400mL) and the organics extracted with n-hexane. The combined organiclayers were washed with water, brine and dried over magnesium sulfate.The solvent was evaporated and the residue purified by columnchromatography (Alumina oxide 90 70-230 mesh, Activity II-III) elutingwith a gradient of 1:9 diethyl ether: hexane to 1:4 diethyl ether.

Example 9 Preparation of O-Ethyl S-(2-Cyanoprop-2-yl)xanthate (72) fromO-Ethyl Xanthogen Disulfide

O-ethyl xanthogen disulfide was prepared by oxidizing an aqueoussolution of potassium O-ethyl dithiocarbonate with I₂/KI (10%) solution.

A solution of O-ethyl xanthogen disulfide (2.16 g, 8.92 mmol) and2,2′-azobis(isobutyronitrile) (2.19 g, 13.35 mmol) in ethyl acetate (30mL) was prepared. The mixture was heated at reflux for 16 hours. Thevolatiles were removed under reduced pressure and the residuechromatographed using a mixture of ethyl acetate:petroleum spirits(3:47) as eluent to isolate the title compound (3.17 g, 94%). ¹H-nmr(CDCl₃) δ 1.52 (t, 3H); 1.75 (s, 6H) and 4.75 (q, 2H). ¹³C-nmr (CDCl₃) δ13.4; 27.2; 40.8; 70.6; 121.1 and 208.2.

Example 10 Preparation of O-Ethyl S-Cyanomethyl Xanthate (73)

A solution of bromoacetonitrile (12.4 g) and potassium O-ethyldithiocarbonate (16.0 g) in ethanol (200 mL) were allowed to stir atroom temperature for 16 hours. The reaction was diluted with water (100mL) and the organics extracted with diethyl ether. The combined organiclayers were washed twice with water, then brine and dried over anhydrousmagnesium sulfate. The solvent was evaporated and the residue purifiedby column chromatography (silica-gel 60, 70-230 mesh) eluting with 4:6ethyl acetate: petroleum spirit 40-60° C. to afford the title compoundas a yellow oil (14.6 g, 90.7%). ¹H-nmr (CDCl₃) δ 1.48 (t, 3H); 3.88 (s,2H); 4.72 (q, 2H). ¹³C-nmr (CDCl₃) δ 13.7, 21.3, 71.5, 115.7, 209.2.

Example 11 Preparation of O-Phenyl S-Benzyl Xanthate (74)

Benzyl mercaptan (1.24 g, 10 mmol) was added to an aqueous (20 mL)solution of NaOH (0.8 g, 20 mmol) at room temperature and stirred for 15minutes. Phenyl thionochloroformate (2.07 g, 12 mmol) was next addeddropwise to this solution at the same temperature and stirred for afurther 2 hours. Diethyl ether (20 mL) and water (50 mL) was added andthe organic layer separated. The aqueous layer was extracted withdiethyl ether (3×20 mL). The combined organic fractions were dried withNa₂SO₄, filtered, the solvent removed and the crude productchromatographed (using silica gel, 2% ethyl acetate in petroleumspirits) to afford the title compound (1.95 g, 75%) as a yellow oil.¹H-nmr (CDCl₃) δ 4.43 (2H), 7.10-7.50 (10H). ¹³C-nmr (CDCl₃) δ 41.7,122.1, 126.7, 127.8, 128.8, 129.3, 129.6, 135.1, 154.0, 213.0.

Example 12 Preparation of O-Pentafluorophenyl S-Benzyl Xanthate (75)

Thiophosgene (1.93 g, 16.6 mmol) in CHCl₃ (10 mL) at 0° C. was treateddropwise with pentafluorophenol in 5% NaOH (15 mL) cooled to 0-10° C.The solution was stirred for 1 hour at the same temperature, the CHCl₃layer separated and washed with 5% NaOH (10 mL), 5% HCl (10 mL) and H₂O10 mL). The organic portions were combined, dried with MgSO₄, filteredand the solvent removed to obtain the perfluorophenyl chloroformate(3.76 g).

Benzyl mercaptan (1.24 g, 10 mmol) was added to 0.8 g of NaOH dissolvedin 20 mL of H₂O and allowed to stir for 10 minutes. The crudechloroformate (2.63 g, 10 mmol) was added to the solution and stirredfor 2 hours. The aqueous solution was extracted with diethyl ether (3×30mL), organic portions combined, dried with Na₂SO₄ filtered and thesolvent removed. The residue was chromatographed with 2% ethylacetate inpetroleum spirits to afford the product (890 mg, 25%). ¹H-nmr (CDCl₃) δ4.5 (2H), 7.3 (5H). ¹³C-nmr (CDCl₃) δ 42.9, 128.2, 128.9, 129.2, 134.0.¹⁹F-nmr (CDCl₃) δ −162.54 (2F, t), −156.94 (1F, t), −151.51 (2F, d).

Examples 13 and 14 illustrate the synthesis of vinylogousdithiocompounds (formula 2 D=D1)

Example 13 Preparation of3-Benzylthio-5,5-dimethylcyclohex-2-ene-1-thione (30)

5,5-Dimethyl-3-piperidinyl-cyclohex-2-en-1-one. Piperidine (7.0 mL;0.0713 mol) and a catalytic quantity of p-toluenesulfonic acidmonohydrate was added to a solution of 5,5-dimethylcyclohexane-1,3-dione(110.0 g; 0.0713 mol) in benzene (100 mL) and the resultant solution washeated at reflux. After 3 hours further piperidine (0.71 mL; 7.13 mmol)was added and the solution was allowed to reflux for a further 16 hours.The reaction mixture was cooled to room temperature and washed with 10%NaHCO₃ solution (20 mL), dried over anhydrous sodium sulfate and thesolvent evaporated (in vacuo) to leave an orange crystalline solid.(14.23 g, 96%). ¹H-nmr (CDCl₃) d: 5.3, (s 1H, H-2), 3.4-3.2 (m, 4H,H-2′, H-6′), 2.2 (s, 2H, H-6), 2.1 (s, 2H, H-4), 1.75-1.4 (m, 6H, H-3′,H-4′, H-5′), 1.00 (s, 6H, 2×CH₃).

5,5-Dimethyl-3-piperidinyl-cyclohex-2-ene-1-thione. The compound wasprepared according to the procedure of Walter, W. and Proll [Walter, W.and Proll, T., Synthesis, 941-2 (1979)]. To a solution of the aboveenamine (1.0 g; 4.82 mmol) in anhydrous DME 10 mL), was added Lawesson'sreagent (1.04 g; 2.57 mmol) over 20 min. at room temperature and underargon. The resulting suspension was stirred at room temperature for 2hours. The mixture was added to ice water 10 mL) and extracted withCH₂Cl₂ (3×20 mL). The combined extracts were dried over anhydrous sodiumsulfate and the solvent evaporated in vacuo to leave an orange solid.The crude solid was chromatographed on a mixture of silica gel and basicalumina (1:1) using chloroform as eluent. The title compound wasobtained as an orange solid (1.1 g, 100%). ¹H-nmr (CDCl₃) d: 6.75 (s,1H, H-2), 3.6-3.4 (m, 4H, H-2′, H-6′), 2.65 (s, 2H, H-6) 2.2 (s, 2H,H-4), 1.75-1.5 (m, 6H, H-3′, H-4′, H-5′), 1.00 (s, 6H, 2×CH₃).

3-Benzylthio-5,5-dimethylcyclohex-2-ene-1-thione. The compound wasprepared according to the procedure of Timokhina et al [Timokhina, L. V.et al, Zh. Org. Khim., 14, 2226-7 (1978)]. To a cold (0° C.) solution ofthe above enaminothione (0.50 g, 2.24 mmol) in anhydrous DMF (5 mL), wasadded benzyl chloride (0.35 g, 2.7 mmol) over 30 min. under Argon. Themixture was allowed to warm to room temperature and stirred for afurther 2 hours. The mixture was cooled to −50° C. (dry ice/benzylacetate) and anhydrous H₂S (g) was passed through the solution for 2hours. The red solution was poured into ice water (10 mL) and extractedwith CH₂Cl₂ (2×20 mL). The combined extracts were dried over anhydroussodium sulfate and the solvent removed in vacuo to give a purple oil(0.52 g. 89%). ¹H-nmr (CDCl₃) d: 7.4-7.1 (m, 5H, ArH) 6.9 (s, 1H, H-2),4.15 (s, 2H, SCH₂Ph) 2.8 (s, 2H, H-6), 2.25 (s, 2H, H-4) 1.00 (s, 6H,2×CH₃).

Example 14 Preparation of Benzyl 3,3-di(Benzylthio)prop-2-enedithioate(76)

Carbon disulfide (0.76 g, 10 mmol) was added dropwise to methylmagnesium chloride (1.67 mL, 5 mmol, 3M solution in diethyl ether) inTHF (3.5 mL) at room temperature. After 2 hours, the solution was cooledto −78° C. (dry ice/acetone) and lithium di-isopropylamide (10 mmol,6.67 mL of 1.5 M solution in hexane) was added over 30 minutes. Thesolution was stirred at −78° C. for 45 minutes, then at room temperaturefor a further 30 minutes before benzyl bromide (1.89 g, 15 mmol) wasadded. The solution was warmed to 40° C. for 2 hours and stirredovernight at room temperature. A 5% solution of NaHCO₃ (30 mL), followedby 20 mL of diethyl ether was added to the mixture and the organic layerseparated. The aqueous layer was extracted with diethyl ether (3×20 mL),the organic layers combined, dried over MgSO₄, filtered and the solventevaporated. The residue was chromatographed on silica gel (5% ethylacetate in petroleum spirits) to afford the product (0.63 g, 29% yield)as an orange solid. ¹H-nmr (CDCl₃) δ 4.19, 4.30, 4.42 (6H, s, CH₂Ph),7.05 (1H, CH), 7.35 (15H, ArH). ¹³C-nmr (CDCl₃) δ 37.6, 39.6, 39.9,124.4 (CH), 124.4, 127.4, 127.7, 128.2, 128.5, 128.7, 129.0, 129.2,129.3, 133.8, 135.4, 136.2. 159.1, 209.4. m/z: AP+ 439 (M+1), AP− 438(M−1).

The following examples demonstrate the application of thedithio-compounds with an α-nitrogen substituent which is an electronwithdrawing/conjugating group to the synthesis of narrow polydispersitypolymers.

Examples 15-19 Styrene Polymerizations in the Presence of α-NitrogenDithio-compounds

Thermal polymerizations of styrene were carried out in the presence ofbenzyl 1-pyrrolecarbodithioate (60), benzyl1-(2-pyrrolidinone)carbodithioate (61), and benzyl(1,2-benzenedicarboximido)carbodithioate (62).

Freshly distilled styrene (1 mL) was added to six separate ampoulescontaining the required amount of dithiocarbamate (see Table 1). Thecontents of ampoules were degassed, sealed and heated at 110° C. for 16hours. After removal of the volatiles, the residue was analyzed by GPC.

TABLE 1 Molecular weight and conversion data for polystyrene prepared inthe presence of dithiocarbamates (60-62) at 110° C. Dithio Examplecompound Dithio (mg) M_(n) M_(w)/M_(n) % Conv. 15 (60) 6.92 30674 1.1858 16 (60) 13.75 16018 1.18 59 17 (61) 7.42 40515 1.63 57 18 (61) 14.8222510 1.58 57 19 (62) 9.07 23480 1.10 51

Example 20 Methyl Acrylate Polymerization in the Presence of a LowConcentration of Benzyl 1-Pyrrolecarbodithioate (60)

A stock solution of the dithiocarbamate (60) (8.6 mg),2,2′-azobis(isobutyronitrile) (3.0 mg) and methyl acrylate (5 mL) inbenzene (20 mL) was prepared. Three 5 mL aliquots of this solution weretransferred to ampoules which were degassed, sealed and heated at 60° C.for 1, 8 and 16 hours respectively. The resulting polymers were analyzedby GPC after the removal of excess monomer and solvent.

TABLE 2 Molecular weight and conversion data for polymerization ofmethyl acrylate in the presence of benzyl 1-pyrrolecarbodithioate (60)(8.6 mg) with 2,2′-azobis(isobutyronitrile) as initiator at 60° C. EntryTime/hr M_(n) M_(w)/M_(n) % Conv. 1 1 37257 1.18 31 2 8 97127 1.37 89 316 110906 1.36 91

Example 21 Methyl Acrylate Polymerization in the Presence of a HighConcentration of Benzyl 1-Pyrrolecarbodithioate (60)

A solution of the dithiocarbamate (60) (86.0 mg),2,2′-azobis(isobutyronitrile) (3.0 mg) and methyl acrylate (5 mL) inbenzene (20 mL) was prepared. Three 5 mL aliquots of this solution weretransferred to ampoules, degassed, sealed and heated at 60° C. for 4, 8and 16 hours respectively. The resulting polymers were analysed by GPCafter the removal of excess monomer and solvent

TABLE 3 Molecular weight and conversion data for polymerization ofmethyl acrylate in the presence of benzyl 1-pyrrolecarbodithioate (60)(86.0 mg) with 2,2′-azobis(isobutyronitrile) as initiator at 60° C.Entry Time/hr M_(n) M_(w)/M_(n) % Conv. 1 4 3381 1.36 22 2 8 5952 1.2247 3 16 8762 1.17 74

The presence of the end groups (pyrrole and benzyl) was confirmed by ¹HNMR.

Examples 22, 23 Methyl Acrylate Polymerization in the Presence of Benzyl1-(2-Pyrrolidinone)carbodithioate (61) and Benzyl(1,2-Benzenedicarboximido)carbodithioate (62)

A stock solution comprising of 2,2′-azobis(isobutyronitrile) (2.30 mg)in benzene (25 mL) was prepared. Aliquots (6.0 mL) were transferred intotwo separate ampoules already containing methyl acrylate (4.0 mL) andthe dithiocarbamate [4.63 mg for (61); 5.20 mg for (62)]. The contentsof both ampoules were degassed, sealed and heated at 60° C. for 16hours.The results are listed in Table 4.

TABLE 4 Molecular weight and conversion data for poly(methyl acrylate)prepared in the presence of (61) and (62) at 60° C. Example DithioesterDithio (mg) M_(n) M_(w)/M_(n) % Conv. 22 (61) 4.63 161800 1.21 89 23(62) 5.20 59800 1.52^(a) 48 ^(a)Bimodal molecular weight distribution.

Example 24 Methyl Acrylate Polymerization in the Presence of2-Cyanoprop-2-yl 1-Pyrrolecarbodithioate (63)

A solution of the dithiocarbamate (63) (8.95 mg),2,2′-azobis(isobutyronitrile) (3.1 mg) and methyl acrylate (5 mL) inbenzene (20 mL) was prepared. Three 5 mL aliquots of this solution weretransferred to ampoules, degassed, sealed and heated at 60° C. for 1, 4and 16 hours respectively. The resulting polymers were analysed by GPCafter the removal of excess monomer and solvent.

TABLE 5 Molecular weight and conversion data for polymerization ofmethyl acrylate in the presence of 2-cyanoprop-2-yl1-pyrrolecarbodithioate (63) with 2,2′-azobis(isobutyronitrile) asinitiator at 60° C. Entry Time/hr M_(n) M_(w)/M_(n) % Conv. 1 1 303081.11 20 2 4 82255 1.13 56 3 16 131558 1.40 91

Example 25 Methyl Acrylate Polymerization in the Presence of Benzyl1-Imidazole Carbodithioate (65)

A solution of the dithiocarbamate (65) (8.6 mg),2,2′-azobis(isobutyronitrile) (2.7 mg) and methyl acrylate (5 mL) inbenzene (20 mL) was prepared. Three 5 mL aliquots of this solution weretransferred to ampoules, degassed, sealed and heated at 60° C. for 1, 4and 16 hours respectively. The resulting polymers were analysed by GPCafter the removal of excess monomer and solvent.

TABLE 6 Molecular weight and conversion data for polymerization ofmethyl acrylate in the presence of benzyl 1-imidazole carbodithioate(65) (8.6 mg) using 2,2′-azobis(isobutyronitrile) as initiator at 60° C.Entry Time/hr M_(n) M_(w)/M_(n) % Conv. 1 1 22189 1.13 16 2 4 82574 1.1466 3 16 107077 1.34 97

Example 26 Methyl Methacrylate Polymerization in the Presence of2-Cyanoprop-2-yl 1-Pyrrolecarbodithioate (63)

A solution of the dithiocarbamate (63) (10.4 mg),2,2′-azobis(isobutyronitrile) (10.1 mg) and methyl methacrylate (7.55mL) in benzene (2.5 mL) was prepared. Four 2 mL aliquots of thissolution were transferred to ampoules, degassed, sealed and heated at60° C. for 1, 4, 8 and 16 hours respectively. The resulting polymerswere analysed by GPC after the removal of excess monomer and solvent.

TABLE 7 Molecular weight and conversion data for polymerization ofmethyl methacrylate with 2-cyanoprop-2-yl 1-pyrrolecarbodithioate (63)using 2,2′-azobis(isobutyronitrile) as initiator at 60° C. Entry Time/hrM_(n) M_(w)/M_(n) % Conv. 1 1 42450 1.70 16 2 4 64025 1.50 51 3 8 1145611.26 >95 4 16 117418 1.27 >95

Example 27 Methyl Methacrylate Polymerization in the Presence of2-Cyanobut-2-yl 1-Pyrrolecarbodithioate (64)

A solution of the CTA (64) (24.97 mg), 2,2′-azobis(2-cyanobutane) (11.7mg) and methyl methacrylate (7.5 mL) in benzene (2.5 mL) was prepared.Four 2 mL aliquots of this solution were transferred to ampoules,degassed, sealed and heated at 60° C. for 2, 4, 8 and 16 hoursrespectively. The resulting polymers were analysed by GPC after theremoval of excess monomer and solvent.

TABLE 8 Molecular weight and conversion data for polymerization ofmethyl methacrylate in the presence of 2-cyanobut-2-yl1-pyrrolecarbodithioate (64) with 2,2′-azobis(2-cyanobutane) asinitiator at 60° C. Entry Time/hr M_(n) M_(w)/M_(n) % Conv. 1 2 193721.58 21 2 4 28752 1.44 52 3 8 35888 1.30 65 4 16 57378 1.21 99

The following example illustrates the effectiveness of a dithiocarbamatewith an α-nitrogen substituent which is a capable of delocalising thenitrogen lone pair in controlling polydispersity of poly(methylmethacrylate). A control experiment carried out withN,N-dimethyl-S-(2-cyanoprop-2-yl) dithiocarbamate (66) shows thatdithiocarbamates with simple alkyl substituents are not effective incontrolling molecular weight or polydispersity.

Example 28 Methyl Methacrylate Polymerization in the Presence of2-Cyanoprop-2-yl-1-Pyrrolecarbodithioate (63) orN,N-Dimethyl-S-(2-cyanoprop-2-yl) Dithiocarbamate (66)

Stock solutions, I comprising 2,2′-azobis(isobutyronitrile) (24.09 mg)in 5 mL of benzene, II comprising N,N-dimethyl-S-(2-cyanoprop-2-yl)dithiocarbamate (66) (5.61 mg) in 2 mL of MMA and III comprising2-cyanoprop-2-yl-1-pyrrolecarbodithioate (63) (15.67 mg) in 5 mL of MMAwere prepared. Four 0.5 mL aliquots of stock solution I were transferredto four ampoules. An aliquot of 1.5 mL of stock solution II wastransferred to one of the above ampoules which was degassed, sealed andheated at 60° C. for 8 hours. Three 1.5 mL aliquots of stock solution mwere transferred to the three remaining ampoules which were degassed,sealed and heated at 60° C. for 2, 8, 16 hours. The respective polymerswere analysed by GPC after removal of excess monomer.

TABLE 9 Molecular weight and conversion data for poly(methylmethacrylate) prepared in the presence of dithiocarbamate derivatives at60° C. Entry Dithio compound Time/hr M_(n) M_(w)/M_(n) % Conv. 1 (66) 8312 462 1.94 >95 2 (63) 2 22 758 1.54 33.2 3 (63) 8 48 257 1.25 92.3 4(63) 16 51 474 1.19 >95

The following example illustrates the effectiveness of a dithiocarbamatewith an α-nitrogen substituent which is a capable of delocalizing thenitrogen lone pair in controlling polydispersity of polystyrene. Acontrol experiment carried out with N,N-diethyl S-benzyl dithiocarbamate(67) shows that dithiocarbamates with simple alkyl substituents are noteffective in controlling molecular weight or polydispersity.

Example 29 Styrene Polymerization Using Benzyl-1-pyrrolecarbodithioate(60) and N,N-Diethyl S-Benzyl Dithiocarbamate (67)

Solutions I of benzyl-1-pyrrolecarbodithioate (60) (55.4 mg) in 8 mL ofstyrene and II of N,N-diethyl S-benzyl dithiocarbamate (67) (14.2 mg) in2 mL of styrene were prepared. 2 mL aliquots of the solution I weretransferred to each of three ampoules which were degassed, sealed andheated at 100° C. for 1, 6 and 30 hours. Solution II was placed in anampoule, degassed, sealed and heated at 100° C. for 6 hours. Therespective polymers were analyzed by GPC after removal of excessmonomer.

TABLE 10 Molecular weight and conversion data for polystyrene preparedin the presence of dithiocompounds (60 & 67) at 100° C. Entry XanthatesTime/hr M_(n) M_(w)/M_(n) % Conv. 5 (67) 6 317 114 1.86 15.3 6 (60) 1 3844 1.63 2.9 7 (60) 6 6 478 1.46 10.2 8 (60) 30 15 605 1.20 59.6

The following example shows that dithiocarbamates with simple alkylsubstituents are effective in controlling molecular weight andpolydispersity of poly(vinyl acetate).

Example 30

Preparation of narrow polydispersity poly(vinyl acetate) in the presenceof N,N-diethyl S-(2-ethoxycarbonylprop-2-yl) dithiocarbamate (69) Astock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile) (2.26mg), vinyl acetate (10 mL) and N,N-diethyl S-(2-ethoxycarbonylprop-2-yl)dithiocarbamate (69) (231.53 mg) was prepared. Aliquots (2 mL) of thisstock solution were then transferred to ampoules. The contents ofampoules were degassed, sealed and heated at 100° C. for specified time.Results are summarized in Table 11.

TABLE 11 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of N,N-diethyl S-(2-ethoxycarbonylprop-2-yl)dithiocarbamate (69) at 100° C. Entry Reaction time (hr) M_(n)M_(w)/M_(n) % Conversion 1 1 4500 1.64 8.4 2 2 6150 1.61 32.4 3 4 95001.47 68.0 4 16 10550 1.43 76.5

The following examples relate to the measurement of transfer constantsof xanthate derivatives in polymerizations of n-butyl acrylate (example31), t-butyl acrylate (examples 32, 33) and methyl methacrylate(examples 34). The magnitude of the transfer constants show that itshould be possible to achieve narrow polydispersities (<1.5) in feedpolymerization processes in polymerizations of acrylate esters.

Example 31 Preparation of Poly(n-butyl Acrylate) in the Presence ofO-Ethyl S-(1-Phenylethyl)xanthate (70)

A stock solution comprising of 2,2′-azobis(isobutyronitrile) (13.4 mg)in benzene (50 mL) was prepared. Aliquots (2 mL) of this stock solutionwere then transferred to four separate ampoules containing n-butylacrylate (4 mL), benzene (4 mL) and O-ethyl S-(1-phenylethyl)xanthate.The contents of ampoules were degassed, sealed and heated at 60° C. forone hour. The results are summarized in the following Table.

TABLE 12 Molecular weight and conversion data for poly(n-butyl acrylate)in the presence of O-ethyl S-(1-phenylethyl) xanthate (70) at 60° C.Entry [CTA]/[MMA] M_(n) M_(w)/M_(n) % Conversion 1 0 1027396 1.78 29 20.00081 70196 1.85 11 3 0.00166 40555 1.77 16 4 0.00325 19411 1.87 12

Analysis of the data via a Mayo plot shows that the transfer constant ofO-ethyl S-(1-phenylethyl)xanthate in n-butyl acrylate polymerization is2.0.

Example 32 Preparation of Poly(t-butyl Acrylate) in the Presence ofO-Pentafluorophenyl S-Benzyl Xanthate (75)

Aliquots (2 mL) of a solution of 2,2′-azobis(isobutyronitrile) (13.4 mg)in benzene (43.7 g, 50 mL) were added to each of four ampoulescontaining t-butyl acrylate (4 mL), benzene (4 mL) and the requiredamount of O-pentafluorophenyl S-benzyl xanthate (75). The ampoules weredegassed, sealed and heated at 60° C. for 60 minutes. Results aresummarized in the following Table.

TABLE 13 Molecular weight and conversion data for poly(t-butyl acrylate)in the presence of O-pentafluorophenyl S-benzyl xanthate (75) at 60°C^(a). [CTA] Entry (mol/L) [CTA]/[M] M_(n) M_(w)/M_(n). Conv. (%) 1 0 01467774 1.68 45.1 2 2.886e-3 1.057e-3 42024 1.83 26.5 3 5.247e-31.922e-3 22214 1.83 24.1 4 1.140e-2 4.176e-3 10850 1.76 16.0 ^(a)[AIBN]= 3.273e-4 M, [t-butyl acrylate] = 2.73 M at 25° C.

Analysis of the data via a Mayo plot shows that the transfer constant ofO-pentafluorophenyl S-benzyl xanthate in t-butyl acrylate polymerizationis 2.7.

Example 33 Preparation of Poly(t-butyl Acrylate) in the Presence ofO-Ethyl S-(2-Cyanoprop-2-yl)xanthate (72)

Aliquots (2 mL) of a solution of 2,2′-azobis(isobutyronitrile) (13.5 mg)in benzene (43.6 g, 50 mL) were added to each of four ampoulescontaining t-butyl acrylate (4 mL), benzene (4 ml) and the requiredamount of O-ethyl S-(2-cyanoprop-2-yl)xanthate (72). The ampoules weredegassed, sealed and heated at 60° C. for 60 minutes. Results aresummarized in the following Table.

TABLE 14 Molecular weight and conversion data for poly(t-butyl acrylate)in the presence of O-ethyl S-(2-cyanoprop-2-yl) xanthate (72) at 60°C^(a). [CTA] Entry (mol/L) [CTA]/[M] M_(n) M_(w)/M_(n). Conv. (%) 1 0 01790182 1.52 38.9 2 2.916e-3 1.068e-3 18775 1.81 7.68 3 5.320e-31.948e-3 9438 1.81 5.13 4 1.053e-2 3.856e-3 4611 1.80 4.26 ^(a)[AIBN] =3.283e-4 M, [t-butyl acrylate] = 2.73 M at 25° C.

Analysis of the data via a Mayo plot shows that the transfer constant ofO-ethyl S-(2-cyanoprop-2-yl)xanthate in t-butyl acrylate polymerizationis 7.25.

Example 34 Preparation of Poly(methyl Methacrylate) in the Presence ofO-Ethyl S-(2-Cyanoprop-2-yl)xanthate (72)

Aliquots (5 mL) of a solution of azobis(isobutyronitrile) (50.3 mg) inmethyl methacrylate (23.4 g, 25 mL) were added to each of four ampoulescontaining the required amount of O-ethyl S-(2-cyanoprop-2-yl)xanthate(72). The ampoules were degassed, sealed and heated at 60° C. for 60minutes. Results are summarized in the following Table.

TABLE 15 Molecular weight and conversion date for poly(methylmethacrylate) prepared in the presence of O-ethyl S-(2-cyanoprop-2-yl)xanthate (72). Entry [CTA]/[MMA] M_(n) M_(w)/M_(n) % Conversion 1 0316205 2.20 13.6 2 0.00073 278090 2.13 13.9 3 0.00176 255183 1.94 13.8 40.00303 233881 1.83 15.3 ^(a)[AIBN] = 1.225e-2 M, [methyl methacrylate]= 9.35 M at 25° C.

Analysis of the data via a Mayo plot shows that the transfer constant ofO-ethyl S-(2-cyanoprop-2-yl)xanthate in methyl methacrylatepolymerization is ca. 0.04.

The following example shows that it is possible to use xanthate estersto control the molecular weight and polydispersity of polymer formed inminiemulsion polymerization.

Example 35 Preparation of Polystyrene via Miniemulsion Polymerizationwith O-Ethyl S-(1-Phenylethyl)xanthate (70) at 70° C.

A 5-neck reaction vessel fitted with a stirrer, condenser andthermocouple was charged with water (75 g) and sodium dodecyl sulfate(215.2 mg), cetyl alcohol (53 mg), sodium bicarbonate (16.7 mg). Themixture was then homogenized for 10 minutes. Styrene (18.84 g) was addedand the mixture homogenized for a further 5 minutes. The reactionmixture was stirred (300 rpm) for 40 minutes while the temperature wasraised to 70° C. O-ethyl S-(1-phenylethyl)xanthate (87 mg) and2,2′-azobis(2-cyano-2-butane) (40.7 mg) were then added.

TABLE 16 Molecular weight and conversion data for polystyrene preparedwith O- ethyl S-(1-phenylethyl) xanthate (70) by mini-emulsionpolymerization at 70° C. Reaction time Example /min M_(n) M_(w)/M_(n) %Conversion control^(a) 60 930564 6.98 13 Ex 35 60 84740 1.4 11 ^(a)noxanthate

The following examples show that it is possible to use xanthate estersto control the molecular weight and polydispersity of vinyl esterpolymers (e.g. vinyl benzoate, vinyl acetate).

Example 36 Preparation of Poly(vinyl Benzoate) in the Presence ofO-Ethyl S-(2-Cyanoprop-2-yl)xanthate (72) at 150° C.

A solution of azobis(isobutyronitrile) (0.14 mL of 1% solotion in vinylbenzoate) and O-ethyl S-(2-cyanoprop-2-yl)xanthate (72) (43.5 mg) invinyl benzoate (3 g) was transferred to an ampoule which was degassed,sealed and heated at 150° C. for 24 hours. A control prepared similarlycontained no xanthate. Results are summarized in the following Table.

TABLE 17 Molecular weight and conversion data for poly(vinyl benzoate)in the presence of O-ethyl S-(2-cyanoprop-2-yl) xanthate (72) at 150° C.Example Reaction time (hr) M_(n) M_(w)/M_(n) % Conversion control^(a) 24381980 2.07 88 Ex 35 24 9140 1.43 12 ^(a)no xanthate

Example 37 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Ethyl S-Cyanomethyl Xanthate (73)

A stock solution (1) of 1,1′-azobis(cyclohexanecarbonitrile) (2.11 mg),vinyl acetate (25 mL) in ethyl acetate (25 mL) was prepared. Aliquot (10mL) of solution (I) was transferred to a 10 mL volumetric flask alreadycontaining O-ethyl S-cyanomethyl xanthate (73) (20.18 mg) for thepreparation of stock solution (II). Aliquots (2 mL) of the stocksolution (II) were transferred to ampoules. The ampoules were degassed,sealed and heated at 100° C. for specified time. Results are summarizedin the following Table.

TABLE 18 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-cyanomethyl xanthate (73) at 100° C. EntryReaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 0.5 1680 1.44 3.4 21.5 11520 1.24 26.6 3 4 20977 1.39 59.7 4 (Control)* 1.5 61560 1.69 40.1*In the absence of O-ethyl S-cyanomethyl xanthate.

Example 38 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Ethyl S-Cyanomethyl Xanthate (73)

A stock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile) (4mg), vinyl acetate (10 mL) and O-ethyl S-cyanomethyl xanthate (73)(160.74 mg) in ethyl acetate (10 mL) was prepared. Aliquots (4 mL) ofthis stock solution were transferred to four separate ampoules. Thecontents of ampoules were degassed, sealed and heated at 100° C. forspecified time. Results are summarized in the following Table.

TABLE 19 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-cyanomethyl xanthate (73) at 100° C. EntryReaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 1 1440 1.23 13.2 2 24600 1.16 40.7 3 6 8420 1.34 82.3 4 16 9095 1.37 91.7

Example 39 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Ethyl S-Cyanomethyl Xanthate (73)

A stock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile) 2.12mg), vinyl acetate (10 mL) and O-ethyl S-cyanomethyl xanthate (73)(160.45 mg), was prepared. Aliquots (2 mL) of this stock solution weretransferred to four seperate ampoules. The contents of ampoules weredegassed, sealed and heated at 100° C. for specified time. Results aresummarized in the following Table

TABLE 20 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-cyanomethyl xanthate (73) at 100° C. EntryReaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 1 615 1.34 7.4 2 22280 1.17 24.5 3 4 7030 1.18 66.3 4 16 10100 1.31 78.3

Example 40 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Etyl-S-(2-Cyanoprop-2-yl)xanthate (72)

A stock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile)(2.10 mg), vinyl acetate (12.5 mL) and O-ethylS-(2-cyanoprop-2-yl)xanthate (72) (23.65 mg) in ethyl acetate (12.5 mL)was prepared. Aliquots (2 mL) of the stock solution were transferred toampoules. The contents of ampoules were degassed, sealed and heated at100° C. for specified time. Results are summarized in the followingTable.

TABLE 21 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-(2-cyanopropyl) xanthate (72) at 100° C. EntryReaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 0.5 577 1.39 1.0 21.5 3350 1.39 9.0 3 4 19300 1.53 66.0 4 16 20750 1.66 93.0

Example 41 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Ethyl S-(2-Ethoxycarbonylprop-2-yl)xanthate (71)

A stock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile)(2.11 mg), vinyl acetate (25 mL) and ethyl acetate (25 mL) was prepared.An aliquot (10 mL) of this solution was transferred to a 10 mLvolumetric flask containing O-ethylS-(2-ethoxycarbonylprop-2-yl)xanthate (71) (29.50 mg) to give a stocksolution. Aliquots (2 mL) of this stock solution were then transferredto each of four ampoules. The contents of ampoules were degassed, sealedand heated at 100° C. for the specified time. Results are summarized inthe following Table.

TABLE 22 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-(2-ethoxycarbonylprop-2-yl) xanthate (71) at100° C. Entry Reaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 0.51010 1.43 1.0 2 1.5 3170 1.39 6.5 3 4 16100 1.22 34.0 4 8 20750 1.5265.5

Example 42 Preparation of Narrow Polydispersity Poly(vinyl Acetate) inthe Presence of O-Ethyl S-Cyanomethyl Xanthate (73)

A stock solution comprising of 2,2′-azobis(isobutyronitrile) (10.09 mg),vinyl acetate (10 mL) and O-ethyl S-cyanomethyl xanthate (73) (160.89mg) was prepared. Aliquots (2 mL) of this stock solution weretransferred to four seperate ampoules. The contents of ampoules weredegassed, sealed and heated at 60° C. for specified time. Results aresummarized in the following Table.

TABLE 23 Molecular weight and conversion data for poly(vinyl acetate) inthe presence of O-ethyl S-cyanomethyl xanthate (73) at 60° C. EntryReaction time (hr) M_(n) M_(w)/M_(n) % Conversion 1 1 326 1.30 4.2 2 2517 1.26 6.0 3 4 866 1.30 9.3 4 16 11670 1.34 91.0

The following examples show that it is possible to use xanthate estersto control the molecular weight and polydispersity of acrylate esterpolymers formed in a batch polymerization process. The lowestpolydispersity is obtained with a xanthate which has an electronwithdrawing substituent on oxygen (E=E2, G=pentafluorophenyl).

Examples 43, 44 Preparation of Narrow Polydispersity Poly(t-butylAcrylate) in the Presence of Xanthate Esters

A solution comprising the xanthate ester in t-butyl acrylate (3.34 g)and ethyl acetate (6.66 g) and 2,2′-azobis(isobutyronitrile) (5.445×10⁻²M) was placed in an ampoule which was degassed, sealed and heated at 60°C. for 60 minutes. Results are summarized in the following Table.

TABLE 24 Molecular weight and conversion data for poly(t-butyl acrylate)in the presence of xanthate esters at 60° C. Ex- am- Xan- [CTA] [M]/ plethate (mol/L) [CTA] M_(n) M_(w)/M_(n) % Conv. con- — 0 0 129174 3.7 >99trol 43 (72) 2.118 × 10⁻² 9.092 × 10⁻³  11032 1.77 71.5 44 (75) 2.148 ×10⁻² 9.219 × 10⁻³  11247 1.40 81.3

Example 45 Styrene Polymerization Using O-Pentafluorophenyl-S-benzylXanthate (75) and O-Phenyl-S-benzyl Xanthate (74)

Solutions I, of O-pentafluorophenyl-S-benzyl xanthate (75) (51.36 mg) in5 mL of styrene, and II, O-phenyl-S-benzyl xanthate (74) (22.92 mg) in 3mL of styrene were prepared. 2 mL aliquots of solution I weretransferred to each of two ampoules which were degassed, sealed andheated at 110° C. for 6 and 20 hours. A 2 mL aliquot of the solution IIwas transferred to an ampoule, degassed, sealed and heated at 110° C.for 6 hours. The respective polymers were analysed by GPC after removalof excess monomer.

TABLE 25 Molecular weight and conversion data for polystyrene preparedin the presence of xanthates (75) and (74) at 110° C. Entry XanthateTime/hr M_(n) M_(w)/M_(n) % Conv. 1 (74) 6 23 698 1.60 24.6 2 (75) 6 14097 1.53 23.7 3 (75) 20 18 862 1.48 57.9

Example 46 Methyl Acrylate Polymerization in the Presence ofO-Pentafluorophenyl-S-benzylxanthate (75) and O-Phenyl-S-benzylxanthate(74)

Stock solutions I, comprising 2,2′-azobis(isobutyronitrile) (3.75 mg) in25 mL of benzene, II, comprising O-phenyl-S-benzylxanthate (39.00 mg) in2 mL of methyl acrylate, and III, comprisingO-pentafluorophenyl-S-benzylxanthate (78.75 mg) in 3 mL of methylacrylate were prepared. 4 mL aliquots of stock solution I weretransferred to each of three ampoules. A 1 mL aliquot of stock solutionII was transferred to one of the above ampoules which was degassed,sealed and heated at 60° C. for 4 hours. 1 mL aliquots of stock solutionIII were transferred to the two remaining ampoules which were degassed,sealed and heated at 60° C. for 4 and 16 hours. The respective polymerswere analysed by GPC after removal of excess monomer.

TABLE 26 Molecular weight and conversion data for poly(methyl acrylate)prepared in the presence of dithio-compounds at 60° C. Entry Dithiocompound Time/hr M_(n) M_(w)/M_(n) % Conv. 1 (74) 4 15 450 1.49 54.3 2(75) 4 12 049 1.47 48.7 3 (75) 16 14 806 1.43 85.6

The following examples demonstrate the use of vinylogous dithioesters inthe synthesis of narrow polydispersity polymers.

Example 47 Polymerization of Styrene in the Presence of3-Benzylthio-5,5-dimethylcyclohex-2-ene-1-thione (30)

The vinylogous dithioester,3-Benzylthio-5,5-dimethylcyclohex-2-ene-1-thione (30) (40.5 mg; 0.154mmol) was dissolved in styrene (5.0 g) (concentration of (17)=0.028M).The solution was equally dispensed into two ampoules which were degassedand heated in an oil bath at 110° C. for 6 and 16 hrs.

TABLE 27 Molecular weight and conversion data for polystyrene preparedby thermal polymerization of styrene in the presence of (30) at 110° C.Entry Time (h) {overscore (M)}_(n) {overscore (M)}_(w)/{overscore(M)}_(n) % conv. 1 6 5528 1.16 10.3 2 16 16561 1.35 25.1

Example 48 Thermal Polymerization of Styrene in the Presence of (76)

A stock solution of the CTA (76) (64.1 mg) in styrene (5 mL) wasprepared. Two 2 mL aliquots of this solution were transferred toampoules which were degassed, sealed and heated at 100° C. for the timesindicated. The volatiles were removed under reduced pressure and theresidues dried to constant weight. The polymers were analyzed by GPC.

TABLE 28 Molecular weight and conversion data for polystyrene preparedby thermal polymerization of styrene in the presence of (76) at 100° C.Entry Time (h) {overscore (M)}_(n) {overscore (M)}_(w)/{overscore(M)}_(n) % conv. 1 6 2393 1.23 9.8 2 64 20982^(a) 1.54 87.7 ^(a)bimodalmolecular weight distribution.

Example 49 Methyl Acrylate Polymerization in the Presence of Benzyl3,3-(Dibenzylthio)propenedithioate (76)

A solution of the CTA (76) (105 mg), 2,2′-azobis(isobutyronitrile) (1.8mg) and methyl acrylate (3 mL) in benzene (12 mL) was prepared. Two 5 mLaliquots of this solution were transferred to ampoules, degassed, sealedand heated at 60° C. for 8 and 16 hours respectively. The resultingpolymers were analysed by GPC after the removal of excess monomer andsolvent.

TABLE 29 Molecular weight and conversion data poly(methyl acrylate)prepared in the presence of benzyl 3,3-(dibenzylthio)propenedithioate(76) using 2,2′-azobis(isobutyronitrile) as initiator at 60° C. ExampleTime (h) {overscore (M)}_(n) {overscore (M)}_(w)/{overscore (M)}_(n) %conv. 1 8 2714 1.22 6.2% 2 16 6390 1.11 9.6%

Example 50 MMA Polymerization Using2-Cyanoprop-2-yl-1-pyrrolecarbodithioate (63)

Stock solutions I, comprising 2,2′-azobis(isobutyronitrile) (24.03 mg)in 5 mL of benzene, and II, comprising2-cyanoprop-2-yl-1-pyrrolecarbodithioate (156.28 mg) in 5 mL of MMA wereprepared. 0.5 mL aliquots of stock solution I were transferred to eachof four ampoules. An aliquot of 1.5 mL of MMA was transferred to one ofthe above ampoules, degassed, sealed and heated at 60° C. for 2 hours(control). Three 1.5 mL aliquots of stock solution II were transferredto the three remaining ampoules, degassed, sealed and heated at 60° C.for 2, 4, 8 hours. The respective polymers were analysed by GPC afterremoval of excess monomer.

TABLE 30 Molecular weight and conversion data for poly(methylmethacrylate) prepared in the presence of dithicarbamate (63) at 60° C.Entry Time/hr M_(n) M_(w)/M_(n) % Conv. 1^(a) 2 274 929 1.67 23.6 2 2 3986 1.35 26.0 3 4 4 992 1.28 53.3 4 8 6 717 1.18 85.7 ^(a)Contol, noadded dithiocarbamate

The following example illustrates the synthesis of a narrowpolydispersity block copolymer.

Example 51 Preparation of Low Polydispersity Poly(methylMethacrylate-block-styrene)

Poly(methyl Methacrylate) (M_(n) 6,717, M_(w)/M_(n) 1.18) was preparedunder the conditions described in example 49. A stock solutioncomprising 2,2′-azobis(isobutyronitrile) (4.5 mg) in 15 mL of styrenewas prepared and the abovementioned poly(methyl methacrylate) (840 mg)was dissolved in 12 mL of this solution. An aliquot of 10 mL of thestyrene, PMMA and 2,2′-azobis(isobutyronitrile) mixture was transferredto an ampoule, degassed sealed and heated at 60° C. for 20 hours. Theresulting polymer was analyzed by GPC after removal of excess monomer.The block copolymer had M_(n) 25 609, M_(w)/M_(n) 1.15 (conversion26.8%).

The following example illustrates the synthesis of a narrowpolydispersity copolymer.

Example 52 Preparation of Low Polydispersity Poly(t-butylAcrylate-co-vinyl Acetate)

A stock solution comprising of 1,1′-azobis(cyclohexanecarbonitrile)(2.30 mg), vinyl acetate (9.34 g) and was prepared. An aliquot (400 ml)of the stock solution was added to an ampoule containing t-butylacrylate (200 ml) and O-pentafluorophenyl-S-benzylxanthate (75) (10.2mg). The ampoule was degassed, sealed and heated at 100° C. for 16hours. The resulting polymer was analysed by GPC after removal of excessmonomer. The copolymer had Mn 16517, M_(w)/M_(n) 1.31 (conversion 68%).

The following examples illustrate vinyl acetate polymerization in thepresence of a conventional chain transfer agent. Polydispersities arestrongly dependent on the particular chain transfer agent and itsconcentration. Where chain transfer constants are high (e.g. a withthiol) broad polydispersities are obtained. Compare example 42 wherenarrow polydispersities are retained throughout the course of thepolymerization to >90% conversion.

Comparative Example 1 Polymerization of Vinyl Acetate in the PresenceCarbon Tetrachloride

A stock solution of 2,2′-azobis(isobutyronitrile) (8.3 mg) in vinylacetate (50 mL) was prepared. Aliquots (10 mL) of this solution weretransferred to ampoules containing various amounts of CCl₄ as shown inTable. The contents of ampoules were degassed, sealed and heated at 60°C. for one hour.

TABLE 31 Molecular weight and conversion date for poly(vinyl acetate)prepared in the presence of carbon tetrachloride as chain transferagent: Entry CCl₄ (g) [CCl₄]/[VAc] M_(n) M_(w)/M_(n) % Conv. 1 (control)0 0 106350 1.9 13.1 2 0.16 0.00958 9800 1.8 9.3 3 0.32 0.01917 5200 1.810.5 4 0.64 0.03834 2600 1.8 10.8

Analysis of the data via a Mayo plot shows that the transfer constant ofcarbon tetrachloride in vinyl acetate polymerization is 0.83.

Comparative Example 2 Polymerization of Vinyl Acetate Using Tert-butylMercaptan

Stock solutions (I), of 2,2′-azobis(isobutyronitrile) (14.3 mg) infreshly distilled Vinyl Acetate (50 mL), and (II), comprising tert-butylmercaptan (20.4 mg) in freshly distilled Vinyl Acetate (10 mL) wereprepared. Four separate ampoules were charged with various amounts ofstock solutions (I) and (II) to give the indicated concentrations. Theampoules were degassed, sealed and heated at 60° C. for one hour.

TABLE 32 Molecular weight and conversion date for poly(vinyl acetate)prepared in the presence of tert-butyl mercaptan as chain transferagent: Entry RSH (mg) [RSH]/[VAc] M_(n) M_(w)/M_(n) % Conv. 1 (control)0 0 112300 1.8 18.7 2 2.04 0.00021 49680 2.9 12.3 3 4.08 0.00042 299504.3 12.1 4 8.16 0.00084 15000 7.5 11.9

Analysis of the data via a Mayo plot shows that the transfer constant oftert-butyl mercaptan in VAc polymerization is 5.97.

What is claimed is:
 1. A process for producing a polymer, said processcomprising polymerizing a monomer mix into said polymer in the presenceof a source of free radicals and a chain transfer agent having atransfer constant in the range of from 0.1 to 5000, said chain transferagent having the following formula:

wherein when D is D1 of the following formula:

then p is in the range of from 1 to 200, E is Z′ and said transfer agentis of the following formula:

wherein when D is D2 of the following formula:

then p is in the range of from 1 to 200, E is E1 or E2 and said transferagent is of the following formula:

wherein when D is D3 of the following formula:

then p′ is in the range of from 2 to 200, E is Z, E1 or E2 and saidtransfer agent is of the following formula:

wherein when D is D4 of the following formula: —S—R′ then E is E3 or E4and said transfer agent is of the following formula:

where in all of the above: R is a p-valent moiety derived from a moietyselected from the group consisting of substituted or unsubstitutedalkane, substituted or unsubstituted alkene, substituted orunsubstituted arene, unsaturated or aromatic carbocyclic ring,unsaturated or saturated heterocyclic ring, an organometallic species,and a polymer chain, R. being a free radical leaving group resultingfrom R that initiates free radical polymerization; R* and R′ aremonovalent moieties independently selected from the group consisting ofa substituted or unsubstituted alkyl, substituted or unsubstitutedalkenyl, substituted or unsubstituted aryl, unsaturated or aromaticcarbocyclic ring, unsaturated or saturated heterocyclic ring,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxy, substituted or unsubstituted dialkylamino, an organometallicspecies, and a polymer chain, R*. being a free radical leaving groupresulting from R* that initiates free radical polymerization; X isselected from the group consisting of a substituted or unsubstitutedmethine, nitrogen, and a conjugating group; Z′ is selected from thegroup consisting of E1, E2, halogen, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, substituted or unsubstituted aryl,substituted or unsubstituted heterocyclyl, substituted or unsubstitutedalkylthio, substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; wherein R″ is selected from the groupconsisting of substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl, substituted orunsubstituted heterocyclyl, substituted or unsubstituted aralkyl,substituted or unsubstituted alkaryl, and a combination thereof; Z″ is ap′-valent moiety derived from a moiety selected from the groupconsisting of a substituted or unsubstituted alkane, substituted orunsubstituted alkene, substituted or unsubstituted arene, substituted orunsubstituted heterocycle, a polymer chain, an organometallic species,and a combination thereof; Z is selected from the group consisting of ahalogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl, substituted orunsubstituted heterocyclyl, substituted or unsubstituted alkylthio,substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; E1 is a substituent functionalityderived from a substituted or unsubstituted heterocycle attached via anitrogen atom or is of the following formula:

 wherein G and J are independently selected from the group consisting ofhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkoxy, substitutedor unsubstituted acyl, substituted or unsubstituted aroyl, substitutedor unsubstituted aryl, substituted or unsubstituted heteroaryl,substituted or unsubstituted alkenyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylsulfonyl, substitutedor unsubstituted alkylphosphonyl, substituted or unsubstitutedarylsulfonyl, substituted or unsubstituted arylsulfinyl, substituted orunsubstituted arylphosphonyl; E2 is of the following formula:

 wherein G′ is selected from the group consisting of substituted orunsubstituted alkenyl, substituted or unsubstituted aryl; E3 is of thefollowing formula

 wherein p′″ is between 2 and 200, G″ is Z″ and J′ is independentlyselected from the group consisting of hydrogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted alkoxy, substituted or unsubstituted acyl, substitutedor unsubstituted aroyl, substituted or unsubstituted aryl, substitutedor unsubstituted heteroaryl, substituted or unsubstituted alkenyl,substituted or unsubstituted alkylsulfonyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylphosphonyl, substitutedor unsubstituted arylsulfonyl, substituted or unsubstitutedarylsulfinyl, substituted or unsubstituted arylphosphonyl or is joinedto G″ so as to form a 5-8 membered ring; and E4 is of the followingformula

 wherein p′″ is between 2 and 200 and G′″ is Z′.
 2. The process of claim1 wherein when p′″=1 and D=D1 then E—C—X=C—Z′ of said chain transferagent forms a cyclic structure.
 3. The process of claim 2 wherein saidchain transfer agent is of the following formula:


4. The process of claim 1 wherein said functionality derived from saidsubstituted or unsubstituted heterocycle is selected from the groupconsisting of pyrrole, imidazole, lactam, cyclic imide, indole,carbazole, benzimidazole, benzotriazole, and isatin.
 5. The process ofclaim 1 wherein said chain transfer agent comprises D1 having thefollowing formula:

when E1 is of the following formula:


6. The process of claim 1 wherein said chain transfer agent comprises D2having the following formula:

when E1 is of the following formula:

or E2 is of the following formula


7. The process of claim 1 wherein said chain transfer agent comprises D2having the following formula:

when E1 is of the following formula:


8. The process of claim 1 wherein said chain transfer agent comprises D2having the following formula:

when E2 is of the following formula: —O—C₂H₅.
 9. The process of claim 1wherein said monomer mix comprises at least one vinyl monomer having thefollowing formula:

where L is selected from tube group consisting of hydrogen, halogen, andsubstituted or unsubstituted C₁-C₄ alkyl, said alkyl substituents beingindependently selected from the group consisting of hydroxy, alkoxy,OR″, CO₂H, O₂CR″, CO₂R″ and a combination thereof; where M is selectedfrom the group consisting of hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂,CONHR″, CONR″₂, O₂CR″, OR″, and halogen.
 10. The process of claim 9wherein said monomer mix further comprises maleic anhydride,N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate, cyclopolymerizablemonomer, a ring opening monomer, a macromonomer or a combinationthereof.
 11. The process of claim 1 wherein said monomer mix comprisesmaleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate, acyclopolymerizable monomer, a ring-opening monomer or a combinationthereof.
 12. The process of claim 1 wherein said substituents areindependently selected from the group that consists of alkyl, aryl,epoxy, hydroxy, alkoxy, oxo, acyl, acyloxy, carboxy, carboxylate,sulfonic acid, sulfonate, alkoxy- or aryloxy-carbonyl, isocyanato,cyano, silyl, halo, dialkylamino, and amido.
 13. The process of claim 1wherein said process is carried out in a polymerization mediumcontaining said chain transfer agent, said monomer mix and said sourceof free radicals.
 14. The process of claim 13 wherein said free radicalsfrom said source of free radicals are introduced to said polymerizationmedium after the addition of said chain transfer agent and said monomermix to said medium.
 15. The process of claim 1 wherein said source offree radicals is selected from the group consisting of a thermalinitiator, redox initiator, photo initiation system, and a combinationthereof.
 16. The process of claim 15 wherein said thermal initiator isselected from the group consisting of 2,2′-azobis(isobutyronitrile),2,2′-azobis(2-cyano-2-butane), dimethyl 2,2′-azobisdimethylisobutyrate,4,4′-azobis(4-cyanopentanoic acid),1,1′-azobis(cyclohexanecarbonitrile), 2-(t-butylazo)-2-cyanopropane,2,2′-azobis[2-methyl-N-(1,1)-bis(hydoxymethyl)-2-hydroxyethyl]propionamide,2,2′-azobis[2-methyl-N-hydroxyethyl)]-propionamide,2,2′-azobis(N,N′-dimethyleneisobutyramidine)dihydrochloride,2,2′-azobis(2-amidinopropane)dihydrochloride,2,2′-azobis(N,N-dimethyleneisobutyramine),2,2′-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide),2,2′-azobis(2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide),2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],2,2′-azobis(isobutyramide)dihydrate,2,2′-azobis(2,2,4-trimethylpentane), 2,2′-azobis(2-methylpropane),t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctoate,t-butyl peroxyneodecanoate, t-butylperoxy isobutyrate, t-amylperoxypivalate, t-butyl peroxypivalate, di-isopropyl peroxydicarbonate,dicyclohexyl peroxydicarbonate, dicumyl peroxide, dibenzoyl peroxide,dilauroyl peroxide, potassium peroxydisulfate, ammonium peroxydisulfate,di-t-butyl hyponitrite, dicumyl hyponitrite and a combination thereof.17. The process of claim 1 wherein said process is carried out at apolymerization temperature in the range of from −20° C. to 200° C. 18.The process of claim 1 wherein said polymer has a polydispersity in therange of from 1.05 to 1.5.
 19. The process of claim 1 wherein saidpolymer is a dispersed polymer or a solution polymer.
 20. A polymer madein accordance with the process of claim
 1. 21. A coating compositioncomprising a polymer made in accordance with the process of claim
 1. 22.The process of claim 1 wherein said polymer is of the following formula:

where n is a positive integer in the range of from 1 to 100,000 andwherein A is of the following formula:

when D is D1 and E is Z′; A is of the following formula:

when D is D2 and E is E1; or A is of the following formula:

when D is D2 and E is E2; and and Q″ is a repeat unit derived from amonomer selected from the group consisting of maleic anhydride,N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate, cyclopolymerizablemonomer, a ring opening monomer, a macromonomer, a vinyl monomer of thefollowing formula:

and a combination thereof; wherein L is selected from the groupconsisting of hydrogen, halogen, and substituted or unsubstituted C₁-C₄alkyl, said alkyl substituents being independently selected from thegroup consisting of hydroxy, alkoxy, OR″, CO₂H, O₂CR″, CO₂R″ and acombination thereof; and wherein M is selected from the group consistingof hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″,OR″, and halogen.
 23. The process of claim 1 wherein said polymer is amixture of isomers of the following formula:

where n is a positive integer in the range of from 1 to 100,000, D isD3, E1 is Z; and Q″ is a repeat unit derived from a monomer selectedfrom the group consisting of maleic anhydride, N-alkylmaleimide,N-arylmaleimide, dialkyl fumarate, cyclopolymnerizable monomer, a ringopening monomer, a macromonomer, a vinyl monomer of the followingformula:

and a combination thereof; wherein L is selected from the groupconsisting of hydrogen, halogen, and substituted or unsubstituted C₁-C₄alkyl, said alkyl substituents being independently selected from thegroup consisting of hydroxy, alkoxy, OR″, CO₂H, O₂CR″, CO₂R″ and acombination thereof; and wherein M is selected from the group consistingof hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″,OR″, and halogen.
 24. The process of claim 1 wherein said polymer is ofthe following formula:

where n is a positive integer in the range of from 1 to 100,000, D isD4, E is E3; and Q″ is a repeat unit derived from a monomer selectedfrom the group consisting of maleic anhydride, N-alkylmaleimide,N-arylmaleimide, dialkyl fumarate, cyclopolymerizable monomer, a ringopening monomer, a macromonomer, a vinyl monomer of the followingformula:

and a combination thereof; wherein L is selected from the groupconsisting of hydrogen, halogen, and substituted or unsubstituted C₁-C₄alkyl, said alkyl substituents being independently selected from thegroup consisting of hydroxy, alkoxy, OR″, CO₂H, O₂CR″, CO₂R″ and acombination thereof; and wherein M is selected from the group consistingof hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″,OR″, and halogen.
 25. The process of claim 1 wherein said polymer is ofthe following formula:

where n is a positive integer in the range of from 1 to 100,000, D isD4, E is E4; and Q″ is a repeat unit derived from a monomer selectedfrom the group consisting of maleic anhydride, N-alkylmaleimide,N-arylmaleimide, dialkyl fumarate, cyclopolymerizable monomer, a ringopening monomer, a macromonomer, a vinyl monomer of the followingformula:

and a combination thereof; wherein L is selected from the groupconsisting of hydrogen, halogen, and substituted or unsubstituted C₁-C₄alkyl, said alkyl substituents being independently selected from thegroup consisting of hydroxy, alkoxy, OR″, CO₂H, O₂CR″, CO₂R″ and acombination thereof; and wherein M is selected from the group consistingof hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂, CONHR″, CONR″₂, O₂CR″,OR″, and halogen.
 26. The process of claim 1 wherein said monomer mixcomprises vinyl acetate, vinyl butyrate, vinyl benzoate, vinyl chloride,vinyl bromide, vinyl fluoride, N-vinylpyrolidone, N-vinylcarbazole or acombination thereof.
 27. The process of claims 1 and 26 wherein D=D2,E=E1 or E2 in said CTA and wherein G, J, and G′ are independentlyselected from the group consisting of substituted or unsubstitutedalkyl, substituted or unsubstituted alkene, substituted or unsubstitutedaryl, substituted or unsubstituted heterocyclyl, with the proviso thatG′ is not substituted or unsubstituted alkyl.
 28. The process of claim27 wherein when E=E1, G—N=J form part of a non-aromatic cyclic group.29. The process of claim 1 wherein said monomer mix comprises amethacrylate, acrylate and styrenic monomers and wherein D=D2, E=E1 andG—N—J forms part of aromatic cyclic group or a non-aromatic cyclic groupwith substituent conjugated to N.
 30. The process of claim 29 where saidsubstituent E1 is substituted or unsubstituted pyrrole, substituted orunsubstituted imidazole, substituted or unsubstituted 2-lactam,substituted or unsubstituted imide.
 31. The process of claim 1 and 25wherein said monomer mix comprises a methacrylate, acrylate, styrenicmonomers and a combination thereof, wherein D=D2, E=E2 in said CTA andwherein G′ is aryl.
 32. The process of claim 31 wherein said aryl isOC₆H₅ or C₆F₆.
 33. A process for producing a polymer, said processcomprising: charging a polymerization medium in a reactor with a chaintransfer agent; introducing a source of free radicals and a monomer mixinto said medium to polymerize said monomer mix into said polymer, saidchain transfer agent having a transfer constant in the range of from 0.1to 5000 and having the following formula:

wherein when D is D1 of the following formula:

then p is in the range of from 1 to 200, E is Z′ and said transfer agentis of the following formula:

wherein when D is D2 of the following formula:

then p is in the range of from 1 to 200, E is E1 or E2 and said transferagent is of the following formula:

wherein when D is D3 of the following formula:

then p′ is in the range of from 2 to 200, E is Z, E1 or E2 and saidtransfer agent is of the following formula:

wherein when D is D4 of the following formula: —S—R′ then E is E3 or E4and said transfer agent is of the following formula:

 where in all of the above: R is a p-valent moiety derived from a moietyselected from the group consisting of substituted or unsubstitutedalkane, substituted or unsubstituted alkene, substituted orunsubstituted arene, unsaturated or aromatic carbocyclic ring,unsaturated or saturated heterocyclic ring, an organometallic species,and a polymer chain, R. being a free radical leaving group resultingfrom R that initiates free radical polymerization; R* and R′ aremonovalent moieties independently selected from the group consisting ofa substituted or unsubstituted alkyl, substituted or unsubstitutedalkenyl, substituted or unsubstituted aryl, unsaturated or aromaticcarbocyclic ring, unsaturated or saturated heterocyclic ring,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxy, substituted or unsubstituted dialkylamino, an organometallicspecies, and a polymer chain, R*. being a free radical leaving groupresulting from R* that initiates free radical polymerization; X isselected from the group consisting of a substituted or unsubstitutedmethine, nitrogen, and a conjugating group; Z′ is selected from thegroup consisting of E1, E2, halogen, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, substituted or unsubstituted aryl,substituted or unsubstituted heterocyclyl, substituted or unsubstitutedalkylthio, substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; R″ is selected from the group consistingof substituted or unsubstituted alkyl, substituted or unsubstitutedalkenyl, substituted or unsubstituted aryl, substituted or unsubstitutedheterocyclyl, substituted or unsubstituted aralkyl, substituted orunsubstituted alkaryl, and a combination thereof; Z″ is a p′-valentmoiety derived from a moiety selected from the group consisting of asubstituted or unsubstituted alkane, substituted or unsubstitutedalkene, substituted or unsubstituted arene, substituted or unsubstitutedheterocycle, a polymer chain, an organometallic species, and acombination thereof; Z is selected from the group consisting of ahalogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl, substituted orunsubstituted heterocyclyl, substituted or unsubstituted alkylthio,substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; E1 is a substituent functionalityderived from a substituted or unsubstituted heterocycle attached via anitrogen atom, or is of the following formula:

 wherein G and J are independently selected from the group consisting ofhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkoxy, substitutedor unsubstituted acyl, substituted or unsubstituted aroyl, substitutedor unsubstituted aryl, substituted or unsubstituted heteroaryl,substituted or unsubstituted alkenyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylsulfinyl, substitutedor unsubstituted alkylphosphonyl, substituted or unsubstitutedarylsulfonyl, substituted or unsubstituted arylsulfinyl, substituted orunsubstituted arylphosphonyl; E2 is of the following formula:

 wherein G′ is selected from the group consisting of substituted orunsubstituted alkenyl, substituted or unsubstituted aryl; E3 is of thefollowing formula

 wherein p′″ is between 2 and 200, G″ is Z″ and J′ is independentlyselected from the group consisting of hydrogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted alkoxy, substituted or unsubstituted acyl, substitutedor unsubstituted aroyl, substituted or unsubstituted aryl, substitutedor unsubstituted heteroaryl, substituted or unsubstituted alkenyl,substituted or unsubstituted alkylsulfonyl, substituted or unsubstitutedalkylsulfinyl, substituted or unsubstituted alkylphosphonyl, substitutedor unsubstituted arylsulfonyl, substituted or unsubstitutedarylsulfinyl, substituted or E4 is of the following formula

 wherein p′″ is between 2 and 200 and G′″ is Z″. said monomer mixcomprising one or more monomers selected from the group consisting ofmaleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate,cyclopolymerizable monomer, and vinyl monomer having the formula:

 where L is selected from the group consisting of hydrogen, halogen, andsubstituted or unsubstituted C₁-C₄ alkyl, said alkyl substituents beingindependently selected from the group consisting of hydroxy, alkoxy,OR″, CO₂H, O₂CR″, CO₂R″ and a combination thereof; where M is selectedfrom the group consisting of hydrogen, R″, CO₂H, CO₂R″, COR″, CN, CONH₂,CONHR″, CONR″₂, O₂CR″, OR″, and halogen.
 34. A chain transfer agenthaving a transfer constant in the range of from 0.1 to 5000, said chaintransfer agent having the following formula:

wherein when D is D1 of the following formula:

then p is in the range of from 1 to 200, E is Z′ and said transfer agentis of the following formula:

wherein when D is D2 of the following formula:

then p is in the range of from 1 to 200, E is E1 or E2 and said transferagent is of the following formula:

wherein when D is D3 of the following formula:

then p′ is in the range of from 2 to 200, E is Z, E1 or E2 and saidtransfer agent is of the following formula:

wherein when D is D4 of the following formula: —S—R′ then E is E3 or E4and said transfer agent is of the following formula:

 where in all of the above: R is a p-valent moiety derived from a moietyselected from the group consisting of substituted or unsubstitutedalkane, substituted or unsubstituted alkene, substituted orunsubstituted arene, unsaturated or aromatic carbocyclic ring,unsaturated or saturated heterocyclic ring, an organometallic species,and a polymer chain, R. being a free radical leaving group resultingfrom R that initiates free radical polymerization; R* and R′ aremonovalent moieties independently selected from the group consisting ofa substituted or unsubstituted alkyl, substituted or unsubstitutedalkenyl, substituted or unsubstituted aryl, unsaturated or aromaticcarbocyclic ring, unsaturated or saturated heterocyclic ring,substituted or unsubstituted alkylthio, substituted or unsubstitutedalkoxy, substituted or unsubstituted dialkyl amino, an organometallicspecies, and a polymer chain, R*• being a free radical leaving groupresulting from R* that initiates free radical polymerization; X isselected from the group consisting of a substituted or unsubstitutedmethine, nitrogen, and a conjugating group; Z′ is selected from thegroup consisting of E1, E2, halogen, substituted or unsubstituted alkyl,substituted or unsubstituted alkenyl, substituted or unsubstituted aryl,substituted or unsubstituted heterocyclyl, substituted or unsubstitutedalkylthio, substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; R″ is selected from the group consistingof substituted or unsubstituted alkyl, substituted or unsubstitutedalkenyl, substituted or unsubstituted aryl, substituted or unsubstitutedheterocyclyl, substituted or unsubstituted aralkyl, substituted orunsubstituted alkaryl, and a combination thereof; Z″ is a p′-valentmoiety derived from a moiety selected from the group consisting of asubstituted or unsubstituted alkane, substituted or unsubstitutedalkene, substituted or unsubstituted arene, substituted or unsubstitutedheterocycle, a polymer chain, an organometallic species, and acombination thereof; Z is selected from the group consisting of ahalogen, substituted or unsubsfituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted aryl substituted orunsubstituted heterocyclyl, substituted or unsubstituted alkylthio,substituted or unsubstituted alkoxycarbonyl, substituted orunsubstituted —COOR″, carboxy, substituted or unsubstituted —CONR″₂,cyano, —P(═O)(OR″)₂, —P(═O)R″₂; E1 is a substituent functionalityderived from a substituted or unsubstituted heterocycle attached via anitrogen atom, or is of the following formula:

 wherein G and J are independently selected from the group consisting ofhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkoxy, substitutedor unsubstituted acyl, substituted or unsubstituted aroyl, substitutedor unsubstituted aryl, substituted or unsubstituted heteroaryl,substituted or unsubstituted alkenyl, substituted or unsubstitutedalkylsulfonyl, substituted or unsubstituted alkylsulfinyl, substitutedor unsubstituted alkylphosphonyl, substituted or unsubstitutedarylsulfonyl, substituted or unsubstituted arylsulfinyl, substituted orunsubstituted arylphosphonyl; E2 is of the following formula:

 wherein G′ is selected from the group consisting of substituted orunsubstituted alkenyl, substituted or unsubstituted aryl; E3 is of thefollowing formula

 wherein p′″ is between 2 and 200, G″ is Z″ and J′ is independentlyselected from the group consisting of hydrogen, substituted orunsubstituted alkyl, substituted or unsubstituted alkenyl, substitutedor unsubstituted alkoxy, substituted or unsubstituted acyl, substitutedor unsubstituted aroyl, substituted or unsubstituted aryl, substitutedor unsubstituted heteroaryl, substituted or unsubstituted alkenyl,substituted or unsubstituted alkylsulfonyl, substituted or unsubstitutedalkylsulfinyl, substituted or unsubstituted alkylphosphonyl, substitutedor unsubstituted arylsulfonyl, substituted or unsubstitutedarylsulfinyl, substituted or unsubstituted arylphosphonyl or is joinedto G″ so as to form a 5-8 membered ring; and E4 is of the followingformula

 wherein p′″ is between 2 and 200 and G′″ is Z″, with the provisos thatwhen D is D2, p=1 and R′ is benzyl or ring substituted benzyl and E isE1 then G and J are not both alkyl, when D is D2, p=1 and R′ is benzyland E is E2 then G′ is not alkyl, when D is D2, p=2 and R is p-xylyleneand E is E1 then G and J are not hydrogen, substituted or unsubstitutedalkyl, substituted or unsubstituted aryl, and when D is D2, p=2 to 12and R is (—CH₂)_(p)Y where Y is p-valent moiety and E is E1 then G and Jare not substituted or unsubstituted alkyl, substituted or unsubstitutedaryl.
 35. The chain transfer agent of claim 34 where D2 is of thefollowing formula:

when E is E1 or E2, wherein E1 is of the following formula:

and E2 is of the following formula:


36. The chain transfer agent of claim 34 where D2 is of the followingformula:

when E1 is of the following formula:


37. The chain transfer agent of claim 34 where D2 is of the followingformula:

when E2 is of the following formula: —O—C₂H₅.
 38. The process of claim 1wherein said polymer a block or gradient copolymer produced bysequentially adding monomers.
 39. The chain transfer agent of claim 34where D is D2 when E is E1 or E2, wherein E1 is of the followingformula:

and E2 is of the following formula:


40. The chain transfer agent of claim 34 where D is D2 when E1 is of thefollowing formula:

with the proviso that R is not benzyl.